In mod rewrite what is the correct way to use a subquery?

Question

htaccess

site in pure html! (burned from the jumulus because the old one and cleaning such sites are already sick of it)
I threw it on a quick .htaccess

RewriteEngine on
RewriteBase /

#убираем инексы как на главнй так и возможные в каталогах.
RewriteCond %{REQUEST_FILENAME} -f
RewriteCond %{REQUEST_URI} ^(.*)/index\.(html|htm)$
RewriteCond %{REQUEST_METHOD} =GET
RewriteRule ^(.*)$ %1 [NC,L,R]


#удаляем всем остальным 
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{THE_REQUEST} ^GET\ /[^?\s]+\.html
RewriteRule (.*)\.html$ /$1 [L,R]

#поскольку реально таких урлов нет нужно  как-то отработать
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-F
RewriteRule ^([^.]+)$ $1.html [NC,L]

Everything works until the moment when it comes across
/catalog.html
and
/catalog
Need:
If there is a catalog.html file, run it while saving ural /catalog
With the current configuration, Apache cannot return Mod_rewrite /catalog/.html
has checks with subqueries, moreover, there are as many as 3 of them, and you can even do it through omission of the condition, but there are so few examples that it is impossible to understand the logic at all.

Answer 1

Usually mod_dir is enabled, which redirects from /catalogto /catalog/if it's an existing directory. Those. needed DirectorySlash Offnot to be/catalog/.html

DirectoryIndex index.html
DirectorySlash Off

RewriteEngine on
RewriteBase /

RewriteCond %{THE_REQUEST} ^GET\ ([^?]*?)(/index)?\.htm
RewriteRule ^ %1 [L,R,NE]

RewriteCond %{DOCUMENT_ROOT}/$1.html -f
RewriteRule ^([^.]+)$ $1.html [L]