Linux needs better multi-monitor support. It's better than it's ever been, but it's still janky and giving black screens on tertiary screens at times.
EDIT: It's funny how the comments are all over the place. "works for me", "it's broken on KDE but works on XFCE", "it's broken on XFCE but works on KDE", etc. I think that's a good sign there are problems with multi-monitor support.
Plasma is probably the worst out of the few bigger DEs. If you don't replug the monitors the same way to the video card, the toolbars you have configured disappear and you cannot copy it from a different display or even make all toolbars identical on all monitors...
Funny because Plasma was the only desktop I tried which game me weird monitor issues
Even Windowmaker worked flawless for me, and my XFCE(Desktop) / i3wm(Laptop) never failed with 3+ monitors
Yeah, KDE was also my first DE but immediately switched to Gnome for 3 Years. Till now after having an AMD card. I guess a lot has changed, i also got way too much issues years back then with Nvidia.
I also saw a difference shortly before switching to AMD with animations on KDE (Gnome went nice with Nvidia). They were either loading, caching or just lagging or smth when hitting the Overview feature (Similar to Gnome super button). This small uncomfy issue instantly went away with AMD for unknown reason.
I've been messing with this on and off for a few years now and I still haven't seen support for multiple monitors running at different scaling levels (like running a 4K monitor at 125% alongside a 1080p monitor at 100%). This is a feature I use in Windows on one of my setups. I hope this gets some attention soon. I run Linux on most of my machines but this problem still gets in my way on others.
Plasma on Wayland can do that I'm pretty sure, and if you don't have an Nvidia GPU Wayland is fine nowadays. Hell, even if you have an Nvidia GPU it's mostly fine nowadays.
How many people total do you think use more than display? How many Linux users or users that would be willing to use Linux would want more than one display? I'm betting it's a lot if not most. So while it may not be a big factor it probably is a factor that applies to most. Then you add up all the other stuff that just doesn't quite work right and you lost the incentive or motivation to switch.
I haven't had any multiple monitor problems since switching to KDE that weren't actually Nvidia driver issues. My "TV" is a third monitor on a long ass HDMI cable.
My only remaining issue is that wayland has slightly more input latency when playing games, enough that it's noticeable (or a very convincing placebo effect).
This makes it so that I have to use X11 and that I have to disable compositioning when playing games as my displays have different refresh rates. All in all, not a big problem but looking forward to be on wayland for good soon.
I had the reverse experience. I have had no issues with multi-monitor (OpenSUSE, nVidia driver direct from nVideas own maintained Opensuse rpms) but on Windows I'm having Windows open black, or delayed, not recognizing external display, etc. Too many variables to make proper apples to apples comparisons.
Xfce have a hard time recognize recently plugged in monitors. I have to restart the PC with the monitors plugged in to have a 50/50 chance to make it work. Or just switch to Cinnamon and make it wok right away.