Admittedly there were a few issues in the past, just nothing in the last couple of years that I can think of.

I was on Linux for about 10 years without a single issues with Firefox until it was turned into a snap package. Slow as hell startup times and other oddities. Removed that and installed from apt and it was back to perfectly stable. Font rendering was always different but I wouldn't say worse. In fact, now that I'm fully back on Windows, the font rendering on Linux is the only thing I really miss. Windows seems a bit blurry in comparison.

Agreed, I have the same experience. I switched to Vivaldi lately because of tab groups, I want to switch back to Firefox because Vivaldi has various annoyances but tab groups are keeping me from going back.

Sideberry extension solves this for me

I'll try that, thanks! The issues I've had with tree-style tabs previously was that I use a portrait screen, so horizontal space is at a premium, and I can't afford a thick sidebar always showing.

The font thing in particular is interesting because Firefox is actually generally ahead of Chrome when it comes to most things related to fonts

https://wpt.fyi/results/css?label=experimental&label=master&...