I’ve gone between a few but on desktop it’s Librewolf. Just like Firefox but more privacy by default. On Android I’ve tried Fennec, Brave, Iceraven, and Mull. Out of all of them Iceraven has been my favorite simply because of its support for desktop extensions.
I like most of the FOSS browsers. Despite not being a Vim user (I know I know) I keep using Qutebrowser on my personal laptop, and I keep boring old Firefox installed too, with just uBlock and a few tiny modifications. I have it there because once every 2 or 3 months I might watch something from Disney+ on my laptop. Might.
On my work laptop I like to keep them on their toes. Librewolf is great, Haven’t tried out Mull yet.
Android is 99% Privacy Browser. I started using it just to give it a test and now I am used to how it works and find it hard to get back to something like Firefox.
I never did feel too keen on Brave or Vivaldi for some reason.