This is related to bug:497073, but I don’t know how to create a backtrace or logs for the panel itself, espescially when the freeze occurs. The crashreport page has been shared there but that is for crashes and not freezes.
Do I need to create a backtrace for freetube or plasmashell, and if so, what would that look like in practice?
Hi - the procedure here in the section titled Retrieving a backtrace with GDB should help you get a usable backtrace for a program that’s not crashing, but freezing up instead 
If you’re trying to get one for plasmashell, then you’d likely need to use the “attach to an existing process” step of providing the existing process ID (pid).