How to make redirect get page request to main page except some pages?

Question

Apache HTTP Server

There is such a structure:
- Main (index.php)
- Login page (signin.php)
- Registration page (signup.php) - User
page (user.php)
- User admin panel (admin.php)
It works like this:
the main page is authorized and a session is created (if there is a session, it redirects to admin.php)
For each user, the user.php page takes the get parameter login. Thus, if you go to site.ru/user.php?login=user1, we will see user1's data from the database.
I want to convert the complex structure site.ru/user.php?login=user1 into site.ru/user1
I write the following in the .htaccess file:

RewriteEngine on
RewriteRule ^(.*)$ user.php?login=$1 [L]

But with this option, when I go to site.ru/user1, I get an error.
If I write:

RewriteEngine on
RewriteRule ^m/(.*)$ user.php?login=$1 [L]

and I turn to site.ru/m/user1, everything works as it should.
The question is how to redirect all site.ru/user.php?login=user1 requests to the main page, but at the same time exclude the registration, login and admin pages? Because if a person goes to site.ru/signin.php = as I understand it, it will be perceived as site.ru/user.php?login=signin.php
In general, I can’t figure it out. Can someone help?
And if possible, immediately with the option to exclude the .php extension in the address bar (whatever .php is shown)

Answer 1

https://habr.com/sandbox/10953/

Answer 2

GET is not part of the url and does not go to the rewrite rule.
To select it, we use a two-level construct
. Also, everything that is $1 from the conda will be %1
# 301 --- www.test.com/faq.html?faq=13&layout=bob => www.test2.com/faqs.html
If host such and such
AND if there is a get request such and such
AND THERE IS NO such and such a request Exception is !
RewriteCond %{QUERY_STRING} !(^|&)layout\=bob2($|&)
THEN execute such a rule
Such a construction is optional. (^|&)faq\=13($|&)
It can be reduced to faq \= 13, but the constitution itself chose the option with and without an upmersant.
Also pay attention to the end of the wheel itself, that at the end it stands ?in such a spelling will remove the get parameters altogether