So I've seen similar issues to this but nothing answers the question with Apache/PHP-FPM

What I'm trying to do: Forward all my requests to index.php without using mod_rewrite.

I'm using the FallbackResource directive inside my vhost.

FallbackResource /index.php

What happens:

mysite.com/anything --> index.php
mysite.com/anything.css --> index.php
mysite.com/anything.html --> index.php
mysite.com/anything.php --> 404 error
mysite.com/anything/anything.php --> index.php

I think the php-fpm is guilty in some way:

# Redirect to local php-fpm if mod_php is not available
<IfModule !mod_php7.c>
<IfModule proxy_fcgi_module>
    # Enable http authorization headers
    <IfModule setenvif_module>
    SetEnvIfNoCase ^Authorization$ "(.+)" HTTP_AUTHORIZATION=$1
    </IfModule>

    <FilesMatch ".+\.ph(ar|p|tml)$">
        SetHandler "proxy:unix:/run/php/php7.4-fpm.sock|fcgi://localhost"
    </FilesMatch>
    <FilesMatch ".+\.phps$">
        # Deny access to raw php sources by default
        # To re-enable it's recommended to enable access to the files
        # only in specific virtual host or directory
        Require all denied
    </FilesMatch>
    # Deny access to files without filename (e.g. '.php')
    <FilesMatch "^\.ph(ar|p|ps|tml)$">
        Require all denied
    </FilesMatch>
</IfModule>
</IfModule>

because i noticed that it's not just .php files but also all the ones listed here: <FilesMatch ".+\.ph(ar|p|tml)$">