As you are using Nginx+Apache2:
Web Template APACHE2
Uses the templates located in /usr/local/hestia/data/templates/web/apache2/php-fpm/
Backend Template PHP-FPM
Uses the templates located in /usr/local/hestia/data/templates/web/php-fpm/
Proxy Template
Uses the templates located in /usr/local/hestia/data/templates/web/nginx/
So take a look to this post, it could be useful for your use case:
Note: In above post, newtemplate.{tpl,stpl} must be located in /usr/local/hestia/data/templates/web/nginx/
That’s because you are not using Nginx standalone so you don’t use fast_cgi cache provided by Nginx.