Which browser? I find Firefox performance unacceptable on ubunutu. I’ve got an nvidia gpu, it feels like Firefox isn’t using it.

Chromium works ok, but I don’t like using chromium.

Do you only have the one 4K display? I guess it depends on the apps you use, but I’ve had to set special scaling settings for individual apps, and that breaks down with multiple mixed-DPI displays.

Yes Bluetooth audio works, but at least on ubunutu I get a long list of MAC addresses and not device names, which has poor usability IMO.

I’ve also noticed Ubuntu with gnome in particular is slow to start apps, and doesn’t give any indication of whether the app is just slow to start or has failed.

Until very recently, Firefox on Linux did not have GPU Acceleration or WebRender. With Firefox 80 and 81, they were added but both were not enabled by default. It may very well be the case that Firefox is not using your GPU.

Regarding mixed-DPI displays and scaling, I have not had issues with GNOME on Wayland.

Bluetooth Audio also works quite well for me, and it shows device names rather than addresses.

I will agree that GNOME tends to be slow to start apps after a while, although it is very quick on fresh installs. I am not sure why that is.

I feel like GPU accel is disabled for most configurations in Firefox on Linux. I had to force-enable it, and perf got quite a bit better (even with dinky Intel graphics).