Set up a local XAMPP server?

Question

linux

When I enter the site address site.ru or site.ru/ or site.ru/123 , /index.html/ is
automatically added to the address,
and since the site does not have such a page, then Error 404 .
I need that by default, when accessing site.ru or site.ru/123/,
the server understands this as site.ru/index.php or site.ru/123/index.php
, I have already revised all the gonfigs - I can’t find where it is configured ,
found only "something similar" to what is needed
in the /opt/lampp/etc/httpd.conf file ,
BUT everything seems to be fine there, put index.php in the first position (it was index.html )
I don’t know where search? where to set it up? (͡๏̯͡๏)
the problem is in the server, not in .htaccess (tried without it)

<IfModule dir_module>
#DirectoryIndex index.html
# XAMPP
DirectoryIndex index.php index.html.var index.html index.php3 index.php4
</IfModule>

PS
here are the configs

/opt/lampp/etc/httpd.conf

[email protected] ~ $ cat /opt/lampp/etc/httpd.conf |grep -v -E "#|^$" 
ServerRoot "/opt/lampp"
Listen 80
LoadModule authn_file_module modules/mod_authn_file.so
LoadModule authn_dbm_module modules/mod_authn_dbm.so
LoadModule authn_anon_module modules/mod_authn_anon.so
LoadModule authn_dbd_module modules/mod_authn_dbd.so
LoadModule authn_socache_module modules/mod_authn_socache.so
LoadModule authn_core_module modules/mod_authn_core.so
LoadModule authz_host_module modules/mod_authz_host.so
LoadModule authz_groupfile_module modules/mod_authz_groupfile.so
LoadModule authz_user_module modules/mod_authz_user.so
LoadModule authz_dbm_module modules/mod_authz_dbm.so
LoadModule authz_owner_module modules/mod_authz_owner.so
LoadModule authz_dbd_module modules/mod_authz_dbd.so
LoadModule authz_core_module modules/mod_authz_core.so
LoadModule authnz_ldap_module modules/mod_authnz_ldap.so
LoadModule access_compat_module modules/mod_access_compat.so
LoadModule auth_basic_module modules/mod_auth_basic.so
LoadModule auth_form_module modules/mod_auth_form.so
LoadModule auth_digest_module modules/mod_auth_digest.so
LoadModule allowmethods_module modules/mod_allowmethods.so
LoadModule file_cache_module modules/mod_file_cache.so
LoadModule cache_module modules/mod_cache.so
LoadModule cache_disk_module modules/mod_cache_disk.so
LoadModule socache_shmcb_module modules/mod_socache_shmcb.so
LoadModule socache_dbm_module modules/mod_socache_dbm.so
LoadModule socache_memcache_module modules/mod_socache_memcache.so
LoadModule dbd_module modules/mod_dbd.so
LoadModule bucketeer_module modules/mod_bucketeer.so
LoadModule dumpio_module modules/mod_dumpio.so
LoadModule echo_module modules/mod_echo.so
LoadModule case_filter_module modules/mod_case_filter.so
LoadModule case_filter_in_module modules/mod_case_filter_in.so
LoadModule buffer_module modules/mod_buffer.so
LoadModule ratelimit_module modules/mod_ratelimit.so
LoadModule reqtimeout_module modules/mod_reqtimeout.so
LoadModule ext_filter_module modules/mod_ext_filter.so
LoadModule request_module modules/mod_request.so
LoadModule include_module modules/mod_include.so
LoadModule filter_module modules/mod_filter.so
LoadModule substitute_module modules/mod_substitute.so
LoadModule sed_module modules/mod_sed.so
LoadModule charset_lite_module modules/mod_charset_lite.so
LoadModule deflate_module modules/mod_deflate.so
LoadModule mime_module modules/mod_mime.so
LoadModule ldap_module modules/mod_ldap.so
LoadModule log_config_module modules/mod_log_config.so
LoadModule log_debug_module modules/mod_log_debug.so
LoadModule logio_module modules/mod_logio.so
LoadModule env_module modules/mod_env.so
LoadModule mime_magic_module modules/mod_mime_magic.so
LoadModule cern_meta_module modules/mod_cern_meta.so
LoadModule expires_module modules/mod_expires.so
LoadModule headers_module modules/mod_headers.so
LoadModule usertrack_module modules/mod_usertrack.so
LoadModule unique_id_module modules/mod_unique_id.so
LoadModule setenvif_module modules/mod_setenvif.so
LoadModule version_module modules/mod_version.so
LoadModule remoteip_module modules/mod_remoteip.so
LoadModule proxy_module modules/mod_proxy.so
LoadModule proxy_connect_module modules/mod_proxy_connect.so
LoadModule proxy_ftp_module modules/mod_proxy_ftp.so
LoadModule proxy_http_module modules/mod_proxy_http.so
LoadModule proxy_fcgi_module modules/mod_proxy_fcgi.so
LoadModule proxy_scgi_module modules/mod_proxy_scgi.so
LoadModule proxy_ajp_module modules/mod_proxy_ajp.so
LoadModule proxy_balancer_module modules/mod_proxy_balancer.so
LoadModule proxy_express_module modules/mod_proxy_express.so
LoadModule session_module modules/mod_session.so
LoadModule session_cookie_module modules/mod_session_cookie.so
LoadModule session_dbd_module modules/mod_session_dbd.so
LoadModule slotmem_shm_module modules/mod_slotmem_shm.so
LoadModule ssl_module modules/mod_ssl.so
LoadModule lbmethod_byrequests_module modules/mod_lbmethod_byrequests.so
LoadModule lbmethod_bytraffic_module modules/mod_lbmethod_bytraffic.so
LoadModule lbmethod_bybusyness_module modules/mod_lbmethod_bybusyness.so
LoadModule lbmethod_heartbeat_module modules/mod_lbmethod_heartbeat.so
LoadModule unixd_module modules/mod_unixd.so
LoadModule dav_module modules/mod_dav.so
LoadModule status_module modules/mod_status.so
LoadModule autoindex_module modules/mod_autoindex.so
LoadModule info_module modules/mod_info.so
LoadModule suexec_module modules/mod_suexec.so
LoadModule cgi_module modules/mod_cgi.so
LoadModule cgid_module modules/mod_cgid.so
LoadModule dav_fs_module modules/mod_dav_fs.so
LoadModule vhost_alias_module modules/mod_vhost_alias.so
LoadModule negotiation_module modules/mod_negotiation.so
LoadModule dir_module modules/mod_dir.so
LoadModule actions_module modules/mod_actions.so
LoadModule speling_module modules/mod_speling.so
LoadModule userdir_module modules/mod_userdir.so
LoadModule alias_module modules/mod_alias.so
LoadModule rewrite_module modules/mod_rewrite.so
<IfDefine JUSTTOMAKEAPXSHAPPY>
LoadModule php4_module        modules/libphp4.so
LoadModule php5_module        modules/libphp5.so
</IfDefine>
<IfModule unixd_module>
User daemon
Group daemon
</IfModule>
ServerAdmin [email protected]
ServerName localhost
<Directory />
    AllowOverride All
    Require all denied
</Directory>
DocumentRoot "/opt/lampp/htdocs"
<Directory "/opt/lampp/htdocs">
    Options Indexes FollowSymLinks ExecCGI Includes
    AllowOverride All
    Require all granted
</Directory>
<IfModule dir_module>
    DirectoryIndex index.php
    DirectoryIndex index.php index.html.var index.html index.php3 index.php4
</IfModule>
<Files ".ht*">
  Require all denied
</Files>
ErrorLog "logs/error_log"
LogLevel warn
<IfModule log_config_module>
    LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\"" combined
    LogFormat "%h %l %u %t \"%r\" %>s %b" common
    <IfModule logio_module>
      LogFormat "%h %l %u %t \"%r\" %>s %b \"%{Referer}i\" \"%{User-Agent}i\" %I %O" combinedio
    </IfModule>
    CustomLog "logs/access_log" common
</IfModule>
<IfModule alias_module>
    ScriptAlias /cgi-bin/ "/opt/lampp/cgi-bin/"
</IfModule>
<IfModule cgid_module>
</IfModule>
<Directory "/opt/lampp/cgi-bin">
    AllowOverride None
    Options None
    Require all granted
</Directory>
<IfModule mime_module>
    TypesConfig etc/mime.types
    AddType application/x-compress .Z
    AddType application/x-gzip .gz .tgz
    AddHandler cgi-script .cgi .pl
    AddType text/html .shtml
    AddOutputFilter INCLUDES .shtml
</IfModule>
EnableMMAP off
EnableSendfile off
Include etc/extra/httpd-multilang-errordoc.conf
Include etc/extra/httpd-autoindex.conf
Include etc/extra/httpd-vhosts.conf
Include etc/extra/httpd-default.conf
<IfModule proxy_html_module>
Include etc/extra/proxy-html.conf
</IfModule>
<IfModule ssl_module>
<IfDefine SSL>
Include etc/extra/httpd-ssl.conf
</IfDefine>
</IfModule>
<IfModule ssl_module>
SSLRandomSeed startup builtin
SSLRandomSeed connect builtin
</IfModule>
Include etc/extra/httpd-xampp.conf

/opt/lampp/etc/extra/httpd-xampp.conf

[email protected] ~ $ cat /opt/lampp/etc/extra/httpd-xampp.conf |grep -v -E "#|^$" 
   LoadModule php5_module        modules/libphp5.so
LoadModule perl_module        modules/mod_perl.so
Alias /phpmyadmin "/opt/lampp/phpmyadmin"
<Directory "/opt/lampp/phpmyadmin">
    AllowOverride AuthConfig Limit
    Require local
    ErrorDocument 403 /error/XAMPP_FORBIDDEN.html.var
</Directory>
AddType application/x-httpd-php .php .php3 .php4
XBitHack on
<IfModule mod_perl.c>
        AddHandler perl-script .pl
  PerlHandler ModPerl::PerlRunPrefork
  PerlOptions +ParseHeaders
        PerlSendHeader On
</IfModule>

/opt/lampp/etc/extra/httpd-default.conf

[email protected] ~ $ cat /opt/lampp/etc/extra/httpd-default.conf  |grep -v -E "#|^$" 
Timeout 300
KeepAlive On
MaxKeepAliveRequests 100
KeepAliveTimeout 5
UseCanonicalName Off
AccessFileName .htaccess
ServerTokens Full
ServerSignature Off
HostnameLookups Off
<IfModule reqtimeout_module>
  RequestReadTimeout header=20-40,MinRate=500 body=20,MinRate=500
</IfModule>