The issue with the taskbar, is there are a couple different implemetation APIs, your shell probably only supports gnome out of the box. I don't recall the name, but there's an extension that will add support for the KDE api for taskbar extensions. I'm running Budgie, with a relatively customized setup, and that was a long while ago, so not as immediately familiar with all that I did.

Will likely switch back to PopOS when the next LTS comes out though.