Two projects on the same domain, how to set up nginx?

Question

Nginx

I have a project with 2 folders

backend - symfony for api

front end-angular

By default, everything should go to index.html, but here are the queries

mydomain.by/api/*****

should already go to the backend.
I poked around for a long time, threw in such a seemingly even working config for nginx

server {
    listen 80;
    listen [::]:80;

    server_name mydomain.by;

    location / {
        root /var/www/mydomain/frontend/dist;
        index index.html;
        rewrite ^(/)/$ $1 permanent;
        try_files $uri /index.html$is_args$args;
    }

    location ~ ^/(api|ping$) {
        root /var/www/mydomain/backend/web;
        # try to serve file directly, fallback to app.php
        try_files $uri /app.php$is_args$args;
    }

    location ~ ^/app\.php(/|$) {
        root /var/www/mydomain/backend/web;
        fastcgi_pass unix:/run/php/php7.1-fpm.sock;
        fastcgi_split_path_info ^(.+\.php)(/.*)$;
        include fastcgi_params;
        # When you are using symlinks to link the document root to the
        # current version of your application, you should pass the real
        # application path instead of the path to the symlink to PHP FPM.
        # Otherwise, PHP's OPcache may not properly detect changes to
        # your PHP files (see https://github.com/zendtech/ZendOptimizerPlus/issues/126
        # for more information).
        fastcgi_param SCRIPT_FILENAME $realpath_root$fastcgi_script_name;
        fastcgi_param DOCUMENT_ROOT $realpath_root;
        # Prevents URIs that include the front controller. This will 404:
        # http://domain.tld/app.php/some-path
        # Remove the internal directive to allow URIs like this
        internal;
    }

    # return 404 for all other php files not matching the front controller
    # this prevents access to other php files you don't want to be accessible.
    location ~ \.php$ {
      return 404;
    }
}

Does anyone have any ideas on how to do this better?