nginx -t passes and nothing changes

The config passes nginx -t, systemctl reload nginx reports success, and behaviour is unchanged.

Three causes. The reload failed silently: systemctl reload only checks that the process got the signal, while nginx keeps the old config on a parse error. Check journalctl -u nginx -n 30 or error.log for emerg.

Or you edited a different file. nginx -t reads /etc/nginx/nginx.conf, but the service may be started with -c pointing elsewhere; look at the master process arguments.

Or the file is not included, or a later server block wins. nginx -T dumps the merged configuration — search for your change there.