@nitinnaresh search is your friend, I have 2 different post on how to enable unsupported Brotli 
You can either install on existing nginx installed by Hestia or replace both are still unsupported so at your own risk
Both of these you need to add in you Brotli settings to enable.
Something like this
brotli on;
brotli_comp_level 6;
brotli_static on;
brotli_types text/xml image/svg+xml application/x-font-ttf image/vnd.microsoft.icon application/x-font-opentype application/json font/eot application/vnd.ms-fontobject application/javascript font/otf application/xml application/xhtml+xml text/javascript application/x-javascript text/plain application/x-font-truetype application/xml+rss image/x-icon font/opentype text/css image/x-win-bitmap;
Option #1 Tested and works fine (Auto update also works)
May 15
If you want to install Brotli that will update its modules when Nginx does use this guide, don’t forget to chmod +x the files you create or when there is an update Nginx will not work.
on this part I set the path directly into /etc/nginx/modules/
moddir=/path/to/modules/directory
Guide link below to create the script, apt hook and worker
https://www.majlovesreg.one/adding-brotli-to-a-built-nginx-instance
Option #2 Replace - In my tests it works fine.
Test on your own install at your own risk and you need to edit the Nginx config file with Hestia specific requirements
Have been playing around with Ubuntu 20.04 install with Hestia 1.2.0 and can confirm Nginx-ee works adding the following features listed, I did find in the Hestia update status still showed older version but that is to be expected it not showing Nginx 1.19.0. Can restart Nginx and edit configs in Hestia panel
Have tested after install and everything is working that was installed, selected OpenSSL from system and added brotli config in nginx config. update to another dev branch did not overwrite settings.
Used app installer for Wordpress which worked fine.
You can choose to auto update by installing the cron job.
- Compile the latest Nginx releases : stable or mainline
- Install Nginx or replace Nginx package previously installed
- Nginx built-in modules selection
- Nginx Third-party modules selection
- Dynamic modules support
- Brotli Support
- TLS v1.3 support (Final)
- OpenSSL (1.1.1g or 3.0.0-dev or from system-lib) or LibreSSL
- Cloudflare HPACK
- Cloudflare zlib
- Automated nginx updates cronjob
- Compilation with GCC-7/8
- Security hardening and performance optimization enabled with proper GCC flags
Compatibility
Recommended
- Ubuntu 20.04 LTS (Focal)
- Ubuntu 18.04 LTS (Bionic)
- Debian 10 (Buster)
Also compatible
- Ubuntu 19.10 (Eoan)
- Debian 9 (Stretch)
Nginx-ee