If you're a really "mainstream" user not really caring about privacy and such use Floorp or Zen.

If you're caring about privacy at least a bit and want to get a pleasing experience, use Waterfox.

If you're a bit more serious about privacy use Librewolf (mainly for privacy itself) or Mullgad Browser (for anonymity and fingerprinting). (These browsers are totally usable if you care about privacy and can be 100% used as daily drivers)

Lastly, you shouldn't use Tor Browser in replacement of the traditional Firefox as it's firstly meant to use it with the Tor network and to only browse some sites that are not tracking every move. (The same goes a bit with Mullvad (excepting the fact that Mullvad is not meant to browser the Tor network), it's an anonymity browser in the sense that you shouldn't use it to connect to the GAFAM fucking services that will suck 100% your datas, in this case of high privacy without really needing pure anti-fingerprinting and anonymity you should use Librewolf)

That's it hope you will succeed in your journey! :)

Last advice : You can also harden the default Firefox with some user.js (like the arkenfox or betterfox one) but as today it's really no more useful in my opinion as forks are doing the same things without the configuration hassle of setting up your new browser. Have a nice day