Nginx as web ui server instead of lighttpd

I have a gl-mv1000 and I would take the advantages of nginx (I need to reverse proxy some server in the lan, later i will use luci-app-acme package to get letsencript certificates for those web servers an the router DDNS name itself… but this is a next step).
I successfully moved lighttpd listen port from 80 to 88 editing the /etc/lighttpd/lighttpd.conf file
then installed luci-ssl-nginx package and configured nginx on port 80 as proxy for lighttpd server. The /etc/nginx/nginx.conf file is as simple as:

user root;
worker_processes auto;
pid /var/run/;

events {
worker_connections 1024;

http {
access_log off;
server {
listen default_server;
server_name _;
location / {
proxy_pass http://localhost:88;

but I don’t like this solution because I get the web interface both at port 80 and 88 (of course firewall could help) while I would completely get rid of lighttpd and serve pages using nginx.

When installing luci-ssl-nginx (or luci-nginx for not https redirect) package it configures a more complex nginx.conf which serves the luci interface correctly but the advantages of gl.inet customized interface is lost.
I can set idx_vue.html as default index page but then it is not working, just asking language selection and new password.

I suppose it is because the cgi server not configured but don’t know how to do.
(in the lighttd configuration there is a /api location but could not do the same working in the nginx config)

You need to set up the cgi working in nginx and it should work fine. Lighttpd does no more than just serving as cgi.