Comment by nfriedly
Yep, you can run Firefox on every Mac released for the past couple of decades. (Maybe more?)
Most of them also work with Linux, although it's a little more spotty on the more recent ARM-based ones ("apple silicon").
Macs are essentially "real computers" that you can run whatever software you want on, whereas iPhones and iPads are much more locked down. (Even when they have the same CPU.)
Yes, and the different browsers on iOS are all actually just skins on top of Safari's WebKit.