What about Microsoft edge?
But Firefox is a good browser and "morally" a better choice for many reasons others have already summarized.
Personally I use Edge as a developer because it's a Chromium browser (so it reflects most of my users' experience and works with a lot of tooling developed for Chrome), I already use Windows 10 and VS Code and it comes preinstalled.
But I used Firefox between the initial release of Quantum and the release of the new Edge browser and while there are both benefits and drawbacks to its dev tooling, it's definitely a good browser and purely on a quality/UX level I see no reason not to use Firefox.
If Edge was still using its own layout engine, I would agree with this. But even on Windows 10, by using Edge you not only trust Microsoft, but also help Google's takeover and control of the internet.
Using Safari, Internet Explorer, Links, Firefox or Serenity Browser all help a bit by reducing the Google browser marketshare. Using Brave, Edge, Vivaldi or Opera still help, but to a much smaller degree.
Oh, serving them your browsing history on a silver plate isn't really the same as letting them infer it from the scraps they could get from other browsers.
PS: and speaking of Chrome mods - Edge is arguably the better one out of all of them. At least with MS we know their policies and main source of revenue, unlike with Brave or Vivaldi.
So 'Google Blink Vivaldi' at best.
Microsoft is terrible. Google is bad. Combining them in a browser was an evil achievement.