If you’re open to using extensions, u can use iceraven, it’s a firefox fork that allows more extensions and tries to make it more compatible with them, although they might not work. I just checked and redirector that was mentioned on the other comment is available there. I use it as my primary mobile browser.
I think it should be fine to sell on steam and also be open source, ppl would rather pirate the compiled version than compile themselves, maybe some license that disallows redistribution or something, so other ppl don’t change a few things and compete with you on steam… Also if it catches the attention of some linux youtubers (more likely if it’s OSS i think) it might give you some extra sales.
Nah, those aren’t Goodenough.