htaccess rewrite rule with 2 variables (1 optional) - .htaccess

Question

I'm aware this has already been asked, but I've tried countless solutions but I'm still not getting the desired result.
I've a page which shows a list of names and the variables data are the starting letter (variable l which can also be a number) and the page number (page_no) and the page number is optional as it should not be displayed in the page 1.
The original URL is the following
https://www.example.com/allnames.php?l=A&page_no=1
I've the following rule
RewriteCond %{QUERY_STRING} ^l=([\w]+)$
RewriteRule ^allnames.php$ /allnames/%1? [R=301,L]
which works fine for page 1, but it doesn't include the page_no variable, so I tried this one but I'm unable to understand what's wrong.
RewriteCond %{QUERY_STRING} ^l=([\w]+)?page_no=([0-9]+)$
RewriteRule ^allmovies.php$ /allmovies/%1/%2? [R=301,L]
the result expected would be, for example
allnames/A or allnames/A/1 for letter A, page 1
allnames/S/8 for letter S, page 8
And the following is the content of the htaccess file
RewriteEngine On
Options +FollowSymLinks -MultiViews
# to prevent loops
RewriteCond %{ENV:REDIRECT_STATUS} !200
#remove index.php
RewriteCond %{REQUEST_URI}::$1 ^(/.+)/(.*)::\2$
RewriteRule ^(.*) - [E=BASE:%1]
# Sets the HTTP_AUTHORIZATION header removed by apache
RewriteCond %{HTTP:Authorization} .
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteCond %{ENV:REDIRECT_STATUS} ^$
RewriteRule ^index\.php(/(.*)|$) %{ENV:BASE}/$2 [R=301,L]
RewriteCond %{REQUEST_FILENAME} -f
RewriteRule .? - [L]
RewriteRule .? %{ENV:BASE}/index.php [L]
# allnames.php
RewriteCond %{QUERY_STRING} ^l=([\w]+)$
RewriteRule ^allnames.php$ /allnames/%1? [R=301,L]
RewriteRule allnames/ /allnames.php?l=$1&page_no=$2 [L]

Answer 1

RewriteCond %{QUERY_STRING} ^l=([\w]+)?page_no=([0-9]+)$
The regex in the condition (CondPattern) does not allow for the & delimiter between URL parameters. You are also allowing the l parameter value to be entirely omitted (which would result in an ambiguous URL) or contain multiple characters (which you've stated should be a single "letter").
You would seem to need something like the following instead:
RewriteCond %{QUERY_STRING} ^l=([\w])&page_no=([0-9]+)$
But note that this will fail if the l parameter value contains more than one character (or is omitted entirely).
the result expected would be, for example
allnames/A or allnames/A/1 for letter A, page 1
Note that you would still need your first rule (without the page_no URL param) to get allnames/A. You could instead make page_no optional in the second rule, but you would still get a trailing slash (ie. allnames/A/) if that is an issue?