Firefox focus isn't firefox, though, it's a private-browsing-only browser, and it's built on an entirely different engine (chromium, iirc). There's no tabs, history, saved logins, or anything else. It's far from being a full-featured browser. Want to disable javascript or images for a while because you're on data? Too bad, you can't.

I'm using Firefox Klar (Firefox Focus for Germany): I have tabs (you can't open an empty tab, but you can open links in a new tab), the session history is enough for my needs, and I can disable JS under settings (and also web fonts, but not images (that's a pity)).

For logins I'm using Keepass Android Offline, Firefox Focus/Klar can use it as autofill service (neither normal FF nor Chrome can do this).

So for me FF Klar/Focus is the best Android browser at the moment, it superseded the normal FF (with ad blocker) on my phone.

Edited: bad autocorrects from Gboard.

You're right that Focus is not a full fledged browser, though it is actively being revamped to use GeckoView instead of Chromium. I think the change is in beta right now.

Mozilla is also starting to put more resources into Android (GeckoView, etc). Hopefully we'll see some exciting things in this realm soon.

Focus is so crippled, for no conceivable benefit (as a user), that I find it unusable. A nice concept, but it can't even switch tabs without causing a full page reload, which is like reverting back to the pre-tabbed-browsing stone-age.

And, as mentioned, it's not even Firefox. It's just a cache-less webkit wrapper.