Yandex is shit and spyware, in the same category of PUP nonsense as Opera GX, even Brave is better than it, and that browser is a waste of your time, being only useful if you cannot get away from the Chromium ecosystem.
The best (privacy-wise) FF-based browser (aside from Tor Browser) right now is Librewolf, being open-source as FF and providing various anti-fingerprinting measures out of the box. A less paranoid, though perhaps more politically-palatable FF browser is Floorp, made by a Japanese company, also open-source, and without the left-wing championing from the project leader of Librewolf (see the Lunduke video on the matter).
From amongst Chromium browsers, you can use Brave if you hate yourself, or ungoogled-chromium if you want to take the time to re-implement the meager privacy and safety changes Brave introduced.