.htaccess how to remove file extensions and index files - regex

Question

I'm trying to achieve a few things through .htaccess ,but keep running into issues. Before you tell me I need to research better and there's already a solution on this or a different forum, please know I've already done that. I always try and figure out things on my own before coming here, but this one is truly stumping me. Everything I've tried has only partially worked. Any help or education here would be truly appreciated.
My site has the following simple structure:
(root)
| index.html
| .htaccess
|
|___portal-folder
| index.php
| home.php
|
|_____admin-folder
| index.php
I'm looking to achieve the following:
When a user navigates to any base directory, for instance site.com or site.com/portal-folder/ they don't see the index file name index.html or index.php in their browser.
Same holds true if the user navigates to the full URL site.com/index.html or site.com/portal-folder/index.php I would like the user to see site.com or site.com/portal-folder/ respectively in their browser.
Strip the file extension off all files in the browser. So for instance navigating to site.com/portal-folder/home.php would show as site.com/portal-folder/home in the browser
The following code I'm using kind of works, but I'm getting strange behavior. For instance:
navigating to site.com/portal-folder/index doesn't remove the index file name and show up as site.com/portal-folder/index instead of site.com/portal-folder/ in the browser
navigating to site.com/portal-folder/ doesn't remove the index file name and shows up as site.com/portal-folder/index.php in the browser.
navigating to site.com/portal-folder/index.php takes the user back to the root site.com
navigating to site.com/portal-folder/home works correctly, but navigating to site.com/portal-folder/home.php doesn't strip the .php extension off.
navigating to site.com works correctly, but navigating to site.com/index.html doesn't remove the index file name.
RewriteEngine On
DirectoryIndex index.html index.php
# remove trailing slash
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{THE_REQUEST} \s(.+?)/+[?\s]
RewriteRule ^(.+?)/$ /$1 [R=301,L]
# To internally forward /dir/file to /dir/file.php
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{DOCUMENT_ROOT}/$1.php -f
RewriteRule ^(.+?)/?$ /$1.php [L]
Server Information: Apache Version 2.4.46

Answer 1

Have it this way:
DirectoryIndex index.html index.php
RewriteEngine On
# To externally redirect /dir/file.php to /dir/file and optionally remove index
RewriteCond %{THE_REQUEST} \s/+(.*?/)?(?:index|(\S+?))(?:\.php|\.html)?[/\s?] [NC]
RewriteRule ^ /%1%2 [R=301,L,NE]
# remove trailing slash
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} ^(.+)/+$
RewriteRule ^ %1 [R=301,NE,L]
# To internally forward /dir/file to /dir/file.php
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{DOCUMENT_ROOT}/$1.php -f
RewriteRule ^(.+?)/?$ $1.php [L]