Rewriting URL from other than root folder with .htaccess - regex

Question

I am trying to make URL rewrite to nice looking URL with .htaccess. I was trying so many ways and always get or error 500 or nothing is happening. My folder tree looks like this:
root
index.php
.htaccess
p
.htaccess
citati.php
...
What I am trying to do is from my "p" directory when someone goes to https://example.com/p/citati/Test-test to rewrite that to https://example.com/p/citati?autor=Test-test so I can have $_GET["autor"] in my citati.php file. I have many .php files in "p" directory so that is also what I need to worry about when rewriting.
This is my .htaccess from root
RewriteEngine on
RewriteCond %{HTTPS} off
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L,NE]
RewriteRule ^(.+)p/citati\/(.+)$ p/citati?autor=$1 [NC]
And this is what I have now in my "p" directory .htaccess file:
<IfModule mod_rewrite.c>
RewriteEngine on
RewriteCond %{REQUEST_FILENAME}.php -f
RewriteRule !.*\.php$ %{REQUEST_FILENAME}.php [L,QSA]
RewriteRule ^p/citati\/(.+)$ p/citati?autor=$1 [NC]
</IfModule>
It doesn't matter if I can achieve this from root .htaccess file or from "p" directory .htaccess I just want somehow to do this.

Answer 1

As per your shown samples, please do have your root's htaccess Rule file as follows.
RewriteEngine ON
RewriteCond %{HTTPS} off
RewriteRule ^ https://%{HTTP_HOST}%{REQUEST_URI} [R=301,L,NE]
For your p directory/folder have that htaccess Rule file as follows. You need to use same rules from root htaccess, you could inherit it.
RewriteOptions InheritBefore
RewriteEngine ON
RewriteBase /p/
RewriteCond %{THE_REQUEST} \s/(citati[^.]*)\.php\s [NC]
RewriteRule ^ %1? [R=301,L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^([^/]*)/(.*)/?$ $1.php?autor=$2 [NC,L]