Centmin Mod LEMP stack installs are pretty optimised out of the box for most as during installation,
Centmin Mod auto detects all server hardware available including memory and cpu cores available and also measures disk i/o speeds etc and
then dynamically optimises the base nginx, php-fpm, mariadb mysql server and tcp settings (if applicable) configurations so they'll be most optimal at time of installation. So Centmin Mod is tailored to each individual server hardware configuration
But if you do have a busy forum, then yes further optimisation is needed beyond the base install time optimal settings and that is usually left up to the end user as I generally don't do free optimisations on the forums and leave it to Centmin Mod users to help each other on official Centmin Mod community forums. Though there are tools provided such as my mysqlmymonlite.sh script for you to gather server stats for tuning
https://community.centminmod.com/threads/mysqlmymonlite-sh-addon.65/. Official site for mysqlmymonlite.sh is at
http://mysqlmymon.com and is used by 1000s of servers
Have you checked on official Centmin Mod community forum's subforum for Forum discussions at
https://community.centminmod.com/forums/forum-software-usage.34/ ? Prefix for Xenforo
https://community.centminmod.com/forums/forum-software-usage.34/?prefix_id=13 and
https://centminmod.com/nginx_configure_xenforo_seo_friendly_urls.html
If you haven't registered yet, you should
https://community.centminmod.com/