I haven't yet learned how to replicate the bug, it keeps happening at seemingly random intervals. Right now it happened after walking away from my pc for a while, and when I got back it happened.
I find my taskbar (Set to be on the bottom) at the top, when I open the edit tool it says that it's still at the bottom. The add widget button just doesn't do anything. The notifications are at the middle of the screen (however they are set to be bottom right).
This all started happening after I updated to plasma6. I searched online and found that typing killall plasmashell && kstart5 plasmashell into alt+space fixes it for a while. But it's not a permanent fix.
Also pre-update I didn't had any problem with my screen going blank while watching Youtube, but now my screen goes to sleep when I watch fullscreen Youtube.
I'm sorry that I got no more information, if I should supply some logs or screenshots, please tell me and I will.
I should've clarified that out of these I've only had the panel issue, with it teleporting to top display for whatever reason. I haven't really looked into it yet, but I think there's at least two bug reports about it where people had the exact issue and had started to figure out what's going on.
I think Tumbleweed just got Plasma 6.0.2, when I get home I'll update to that and see if that solves it.
I have similarly annoying issues when one of monitors is turned off. It collapses everything back onto the other display and doesn't reset when I turn it back on.
So maybe an issue with the display going to sleep?
Could be, as I recall it happening when I walked back to my pc. Yesterday I set the sleep to 1 minuted and played with it a bit, couldn't replicate it. As a matter of fact it didn't even happen on it's own. I haven't updated so idk what's going on.
Check under Display Configuration, its at the top of the list where Gamma is in your screenshot. I'm also using Wayland, so maybe its not available for X11?
I had a bunch of mild but annoying breakage since the update as well. What helped me is renaming .cache and .config, rebooting and just copying select things over to the fresh folders
I had similar issues. When first booting into plasma6, my bottom panel was changed to floating. Changing it to not float made it spaced from the bottom of the screen.
While trying to fix that, I somehow managed to move the pinned icons all off the panel and onto the desktop, but they were unable to be clicked or moved. I ended up restarting for unrelated reasons and they snapped back to the panel.
I think there were other wonky issues with the edit session, but I don't recall specifics. Good luck!
Edit: this was on a wayland session with integrated amd graphics.
There are systems where killall does just that (kills all processes). If you get used to it and end up on one of those, it could end up poorly.
pkill kills by matching the process name. So that's probably what you want. You probably want to use the -HUP (hangup) signal at first (it may send that by default, not sure) before using a kill.