“Come on, Valve. Do something!”
“Come on, Valve. Do something!”
It is great. I have been using Linux for about three years and majority of that was with KDE Plasma and its Wayland session. Most of that time was with Arch and Fedora and it was all smooth sailing.
It was faster and smoother than GNOME Shell, Cinnamon or any other desktop I have tried.
It may have slightly more bugs compared to GNOME Shell due to sheer amount of features it has.
As others have mentioned, you might have a hardware issue that coincidentally pops up with Plasma.
What you are referring to are the window decorations.
Apart from Linux Mint, Firefox almost always uses client-side decorations. What you are showing here is still client-side.
It is just that Mozilla recently enabled vertical tabs option for everyone, so the top bar is now slightly smaller than before. You can disable vertical tabs easily by searching in the settings.