Linux has now hit 3% according to sat counter. It isn’t has obscure as it was in the past and I think it is a lot less of a privacy risk.
I also know a significant number of Linux users who use librewolf. This means that the user share might be a bit higher
I’m thinking it should mimic the most common user agent available (guessing Edge’s whatever it is), refreshed on updates. At the very least it should be far easier to configure. As it stands changes in About:config are not recognized.
Your browser engine is very easy to identify, it would be useless to lie and it would also cause a lot of breakage.