How to properly set up a 301 redirect for Wordpress so that the admin panel works?

Question

Apache HTTP Server

Good afternoon,
I am replacing the site from MODx to WP. On the previous site, a redirect from ibtwo.ru to assets.bibic.com (fake site names) was configured as follows:

# MODx supports Friendly URLs via this .htaccess file. You must serve web
# pages via Apache with mod_rewrite to use this functionality, and you must
# change the file name from ht.access to .htaccess.
#
# Make sure RewriteBase points to the directory where you installed MODx.
# E.g., "/modx" if your installation is in a "modx" subdirectory. If you have
# problems with your .htaccess working at all, try un-commenting the first 
# line above the "RewriteEngine On" directive.
#
# You may choose to make your URLs non-case-sensitive by adding a NC directive
# to your rule: RewriteRule ^(.*)$ index.php?q=$1 [L,QSA,NC]

AddDefaultCharset UTF-8

#Options +FollowSymlinks
RewriteEngine On
RewriteBase /


# Fix Apache internal dummy connections from breaking [(site_url)] cache
RewriteCond %{HTTP_USER_AGENT} ^.*internal\ dummy\ connection.*$ [NC]
RewriteRule .* - [F,L]


# Rewrite www.domain.com -> domain.com -- used with SEO Strict URLs plugin
#RewriteCond %{HTTP_HOST} .
#RewriteCond %{HTTP_HOST} !^example-domain-please-change\.com [NC]
#RewriteRule (.*) http://example-domain-please-change.com/$1 [R=301,L]
#
# or for the opposite domain.com -> www.domain.com use the following
# >>> DO NOT USE BOTH THE ABOVE AND BELOW <<<
#
#RewriteCond %{HTTP_HOST} .
#RewriteCond %{HTTP_HOST} !^www\.example-domain-please-change\.com [NC]
#RewriteRule (.*) http://www.example-domain-please-change.com/$1 [R=301,L]

RewriteCond %{HTTP_HOST} !^assets\.bibic\.com [NC]
RewriteRule (.*) http://assets.bibic.com/$1 [R=301,L]


# Rewrite secure requests properly to prevent SSL cert warnings, e.g. prevent 
# https://www.domain.com when your cert only allows https://secure.domain.com
#RewriteCond %{SERVER_PORT} !^443
#RewriteRule (.*) https://example-domain-please-change.com.com/$1 [R=301,L]

#Redirect /en http://ibtwo.ru

# The Friendly URLs part
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php?q=$1 [L,QSA]

#Redirect /en http://ibtwo.ru
#RewriteEngine On
#RewriteCond %{HTTP_HOST} ibtwo.ru/en^
#RewriteRule (.*) http://www.ibtwo.ru/$1 [R=301,L] 


# Make sure .htc files are served with the proper MIME type, which is critical # for XP SP2. Un-comment if your host allows htaccess MIME type overrides.

#AddType text/x-component .htc



# If your server is not already configured as such, the following directive
# should be uncommented in order to set PHP's register_globals option to OFF.
# This closes a major security hole that is abused by most XSS (cross-site
# scripting) attacks. For more information: http://php.net/register_globals
#
# To verify that this option has been set to OFF, open the Manager and choose
# Reports -> System Info and then click the phpinfo() link. Do a Find on Page
# for "register_globals". The Local Value should be OFF. If the Master Value
# is OFF then you do not need this directive here.
#
# IF REGISTER_GLOBALS DIRECTIVE CAUSES 500 INTERNAL SERVER ERRORS :
#
# Your server does not allow PHP directives to be set via .htaccess. In that
# case you must make this change in your php.ini file instead. If you are
# using a commercial web host, contact the administrators for assistance in
# doing this. Not all servers allow local php.ini files, and they should
# include all PHP configurations (not just this one), or you will effectively
# reset everything to PHP defaults. Consult www.php.net for more detailed
# information about setting PHP directives.

#php_flag register_globals Off



# For servers that support output compression, you should pick up a bit of
# speed but un-commenting the following lines.

#php_flag zlib.output_compression On
#php_value zlib.output_compression_level 5



# The following directives stop screen flicker in IE on CSS rollovers. If
# needed, un-comment the following rules. When they're in place, you may have
# to do a force-refresh in order to see changes in your designs.

#ExpiresActive On
#ExpiresByType image/gif A2592000
#ExpiresByType image/jpeg A2592000
#ExpiresByType image/png A2592000
#BrowserMatch "MSIE" brokenvary=1
#BrowserMatch "Mozilla/4.[0-9]{2}" brokenvary=1
#BrowserMatch "Opera" !brokenvary
#SetEnvIf brokenvary 1 force-no-vary

The new site on Wordpress .htaccess looks like this:

# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPress

If you simply replace the Wordpress .htaccess with the old one, then the site works, all redirects are made, but it is impossible to enter the admin panel, after entering the username and password, we do not go anywhere.

Question: how to combine these two .htaccess correctly?
I don't understand much about .htaccess settings, but I will learn, but for now I just need prompt help.
Thank you very much in advance!