How to migrate backend from apache to nginx?

Question

Nginx

Now the following scheme is working:
apache - backend, nginx - frontend. Used by fastcgi for phpmyadmin.
Periodically, the site freezes, apache spawns a bunch of processes and loads the machine, so that the site stops working.
At the root of the site there is .htaccess that apache reads, I saw there is a recoder for nginx. But which rules should be transferred and which should not?
Is there a step-by-step, up-to-date migration guide? There are a lot of articles on the Internet from 2012 and older.

Answer 1

1) it is not clear from your explanation what exactly is on the backend? PHP over FastCGI through Apache? Or are you talking about fcgi for a catchphrase?
2) NginX does not know how to interpret php on its own (unlike Lua and Perl) and for it you will need to run php-fpm and hook it up.
There is a rule recoder from .htaccess, but it does too much on if, which is wrong. So just give your .htaccess here and I'll rewrite it for rewrites.