Pretty URLs .htaccess rewrite engine

I'd like to combine two rules together so I could have pretty URLs

both of index - mysite.com/en => mysite.com/?lang=en as well as further directories - mysite.com/en/blog/trip => mysite.com/blog/trip?lang=en

my .htaccess file looks like this, I tried to use the code from here but that works just for the second part of my problem

# Default index
DirectoryIndex index.php

RewriteEngine On

# Rewrite "/<lang>/<directory>/" to `/<directory>/index.php?lang=<lang>"
RewriteCond %{DOCUMENT_ROOT}/$2/index.php -f
RewriteRule ^([a-z]{2})/(.*?)/?$ $2/index.php?lang=$1 [L]

# Rewrite "/<lang>/<directory>/<file>" to `/<directory>/<file>?lang=<lang>"
RewriteCond %{DOCUMENT_ROOT}/$2 -f
RewriteRule ^([a-z]{2})/(.+) $2?lang=$1 [L]

# add .php extension 
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteRule ^(.+?)/?$ $1.php [L]

Thank you for your time!

source https://stackoverflow.com/questions/77208109/pretty-urls-htaccess-rewrite-engine