htaccess 404 error on language subfolder (en/) - php

Question

I have the following structure:
/
/about.php
/contact.php
/en/
/en/about.php
/en/contact.php
And I want to remove .php extension and www prefix from the urls and force https as well.
Now I have the following htaccess:
RewriteEngine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteRule ^([^/]+)/$ $1.php
RewriteRule ^([^/]+)/([^/]+)/$ /$1/$2.php
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_URI} !(\.[a-zA-Z0-9]{1,5}|/)$
RewriteRule (.*)$ /$1/ [R=301,L]
Thanks in advance for any help!

Answer 1

You're really close as far as what you have. Now that I know the issue I'll give you what I use -- You need a condition that says is not a directory -- And the syntax is !-d
This is how my htaccess looks (because I use it to remove html as well as php:
RewriteEngine on
# Redirect www and http to https - non-www
RewriteCond %{HTTPS} off [OR]
RewriteCond %{HTTP_HOST} ^www\. [NC]
RewriteCond %{HTTP_HOST} ^(?:www\.)?(.+)$ [NC]
RewriteRule ^ https://%1%{REQUEST_URI} [R=301,L]
# Start php extension remove
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^(.*)$ $1.php
# End php extension remove
# Start html extension remove
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.html -f
RewriteRule ^(.*)$ $1.html
# End html extension remove
As you can see the first condition checks to see that it's not a directory. The following condition checks to see if it's file extension is .php. If both conditions are true -- The rule is to remove the extension.
As a note -- I would make your syntax a little cleaner and separate the "sections" of what you are trying to do.
UPDATE AS PER COMMENT
To remove the https forcing -- Simply comment out the first condition and change https to http in the rule:
RewriteEngine on
# Redirect www and http to https - non-www
#RewriteCond %{HTTPS} off [OR]
RewriteCond %{HTTP_HOST} ^www\. [NC]
RewriteCond %{HTTP_HOST} ^(?:www\.)?(.+)$ [NC]
RewriteRule ^ http://%1%{REQUEST_URI} [R=301,L]
# Start php extension remove
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.php -f
RewriteRule ^(.*)$ $1.php
# End php extension remove
# Start html extension remove
RewriteCond %{REQUEST_FILENAME} !-d
RewriteCond %{REQUEST_FILENAME}\.html -f
RewriteRule ^(.*)$ $1.html
# End html extension remove