Plasma was hanging ridiculously when starting up. Like 10-15 minutes to load. Once a window like dolphin or web browser was up it would work fine and fast in the app, but the menu, task manager, panel, and icons on the desktop would hang. plasmashell seemed to be the culprit, but restarting it never fixed anything. I changed plasmashell priority to "high" and that seemed to help somewhat, but it didnt fix the issue. I attempted to turn off anything that might be causing it to hang, with no luck. Long story short, when I found the activities settings under desktop behavior, I went to the privacy tab and it was set to remember opened documents for all applications as well as keep history forever. I cleared activity history and after I did so a couple firefox windows popped up and suddenly things started moving faster. I now have it set to "do not remember" for opened documents and when starting up it starts up in seconds compared to the 10-15 minutes I would have had to wait before. Huge huge difference and I felt like it was worth sharing how I fixed the issue in case it helps anyone else. I am 99% certain that no other factor could have been the cause of plasmashell hanging because I had just done a fresh restart and the activities setting is the only thing I changed before restarting again and it is now working faster.