The problem with stats like these are that Firefox users (and the browser's defaults) block a lot of the scripts and images used for tracking.
Cloudflare's stats show higher Firefox usage (4.737% for 2023 Q3), although that's still less than even Edge. My own logs show more still, although my visitors are more technical than usual.
You're assuming that we can't have both. Why not have it as an complementary input?
I think looking at a device and talking is better than saying hey $brandname before everything, but having both would be better still.