I only use Brave for my school work and to watch netflix, everything else I do on FF. If you feel like FF is slow compared to chromuim based browsers, you should try and optimize/harden FF and see the differences for you.

Personally FF is alot lighter and faster for me than Brave for searching the web and Is what I choose to use in the background when I play games because of how light it is compared to brave.

Also since your using Brave you should turn on "Upgrade connections to HTTPS" to Strict! Just a recommendation!

Have a nice day!~