301 redirect with Nginx map module

Hi! I have a large wordpress project with thousands of pages. I want to migrate it to Forem. We wrote a migration script for that using Forem API. I have to do a mass 301 redirect from old pages to new ones to not loose positions in search engines.

Google has suggested that the best way to do mass redirects is to use Nginx map module. At first glance, everything there is simple. Create a file with redirects, plug it into the Nginx file and create rules.

First, i create a new file:

/opt/forem/configs/regex.map

File regex.map:

/old /varhal/podborka-topovykh-biesplatnykh-sietov-ikonok-dlia-dizainiera-1e4b;


After i edited nginx.conf:

/opt/forem/configs/nginx.conf

Include map file:

map $request_uri $new_uri {
include /opt/forem/configs/regex.map;
}

Add code to server section (variant 1):

server {
...
if ($new_uri != "") {
rewrite ^(.*)$ $new_uri permanent;
}
...
}

Add code to server section (variant 2):

server {
...
if ($new_uri) {
return 301 $new_uri;
}
...
}

After all the manipulation, different versions of code and errors redirect did not work. When you go to a page that should be redirected, there is a wait of several minutes and redirect does not work. In some cases when I redirected to the main page, after the redirect the page looked like this :
example.com:9090 and it didn't work.

Need help from the community, thanks!

Use this tutorials:

https://gauravswaroop.medium.com/nginx-bulk-url-redirect-with-map-47c2cd6ad50a

https://stackoverflow.com/questions/29354142/nginx-how-to-mass-permanent-redirect-from-a-given-list