bro that is why above i said nginx backend as webserver and varnish as frontend cache server to cache webpages
others panels are already using ..
1.https://forum.mratwork.com
they have option to enable Apache+Nginx with varnish and other options many.
2.http://centos-webpanel.com
they also have same options Apache with varnish and Nginx withvarnish and Apache with Nginx +varnish.
3.https://www.plesk.com
they also have option to Apache with nginx and with nginx cache or with Apache with nginx with Varnish on docker
and other panel have too varnish like Cpanel with addons