I recently switched to Firefox Nightly on Android and haven't noticed it being any slower than the previous chromium browser I was using. I did opt to forgo the Dark Reader add-on for it though since that was slowing down webpage rendering a bit.
The issue for me with Firefox on Android is it would sometimes refuse to load pages when switching back after being suspended from the background and I have no clue why. I'd have to open a new tab and copy the URL to force it to load and it was so frustrating.
I use Brave now (with the promotional stuff off, even though I still don't fully trust them), since it seems to be the only other ad-blocking browser on Android that's even decently easy to use. However, I still use Firefox on Windows with tree style tabs and raindrop.io to sync bookmarks, both of which are god tier productivity tools.
No work around is needed. You can install a very limited number of extensions on Firefox mobile and they are the ones you want the most. This includes uBlock Origen.
You don't know which extensions I want most. I want:
uBlock Origin ✅
Consent-o-Matic ❌ - but the sort of thing they might eventually add to the blessed list with enough begging
Bypass Paywalls ⛔ - Mozilla will never recommend this or even distribute it on its addons site
3-4 years ago, I could install any extension I wanted. I reject their stated reasons for barring me from doing so (security, stability - those are on me once I start installing unsupported add-ons) and use Kiwi Browser instead.