Firefox is certainly a good alternative to Chrome and Google (despite the relationship it has with this moloch), but Vivaldi too. Vivaldi use Blink, but with this ends any similarity or relationship with Chrome and Google. And speaking about Privacy, FF is is not much better (at least if you don't sync with Mozilla, which share data with Alphabet.Inc).

Vivaldi don't share nothing to third parties, because it don't have third party investors and don't make money with surveillance advertising. In customization Vivaldi is Lightyears above any other Browser without any doubts. You can change anything in Vivaldi, Menu's, UI, Icons and much more, or use one of the more than 4.000 Themes, created by the users

The only you can say is, that the alternatives to Chrome and Edge are running out, of more than 100 browsers that currently exist, only Firefox (maybe also some not too much outdated forks), Vivaldi and perhaps Otter Browser, remain as usable, nothing else.