How it is possible without using if but with map in nginx with the module --with_geoip2_module (dynamic) to block all countries except the chosen and all ip except the chosen, to make it work like this:
**if ($lan = yes) {
              set $allowed_country yes;
      }
if ($allowed_country = no) {
       return 503;
  }**
but without if?
Centos 7
It`s my /etc/nginx/nginx.conf
load_module modules/ngx_http_geoip2_module.so;
user nginx;
worker_processes  1;
error_log  /var/log/nginx/error.log warn;
pid        /var/run/nginx.pid;
events {
    worker_connections  1024;
}
http {
    include       /etc/nginx/mime.types;
    default_type  application/octet-stream;
#block country
 geoip2 /etc/nginx/geoip/GeoLite2-Country/GeoLite2-Country.mmdb {
auto_reload 60m;
$geoip2_data_country_code country iso_code;
$geoip2_data_country_name country names en;
}  
geo $lan {
 default no;
 123.224.55.2 yes;
  }
map $geoip2_data_country_code $allowed_country {
    
    default no;
    UA yes;
    BG yes;
    RO yes;
}
   log_format geoip_main '$remote_addr - $geoip2_data_country_code - $remote_user [$time_local] '
                           '"$request" $status $body_bytes_sent "$host" '
                           '"$http_referer" "$http_user_agent" "$gzip_ratio"';
access_log  /var/log/nginx/access.log geoip_main;
access_log /var/log/nginx/geoip_country.log geoip_main;
    sendfile        on;
    #tcp_nopush     on;
    keepalive_timeout  65;
access_log /var/log/nginx/geoip_country.log geoip_main;
    sendfile        on;
    #tcp_nopush     on;
    keepalive_timeout  65;
    #gzip  on;
    include /etc/nginx/conf.d/*.conf;
 include include/etc/nginx/modules/*.so;
}
I am very grateful to you for your help!
                        
An official NGINX article says:
So your
if (...) { return 503; }block is completely safe. To exclude first oneifblock, useUpdate
This version have the same functionality and should be slightly faster since it doesn't use a regex matching: