It's been 13 years of "no, you can't do in the phone's webbrowser the thing you can do in a PC's webbrowser, you need to install a fucking app". People just accepted it. The fuckers accepted it.
I used UAS on Librewolf specifically to say I'm on Firefox and Linux (which I am). I want to properly represent what I'm using and not support the Google/Microsoft monopolies, even if that means some websites throw around unsupported browser or OS errors.
I'm willing in this case. The less people hide their actual user-agent (and not use chromium or windows in general), the less valuable that information becomes anyways. I like to think of it as sacrificing myself for the benefit of all.
Thank fuck early desktop GUIs used the resizable windows multi-tasking paradigm.
Potentially having tiny browser windows means that every website will have to be somewhat responsive just to get usage in corporate offices. I'd much rather have to spoof being a smol bean chrome window than install every shitty app.