I haven’t seen anywhere a way to MANUALLY install the new KDE 5.21? I am running Ubuntu 20.10, and it isn’t coming down with any of my updates…any ideas how to manually install this anyone?
Hello 
. Not sure if possible (not easily, anyway). You could try to first install the KDE Plasma desktop environment on Ubuntu 20.10, then maybe use the “Backports PPA” to get the latest KDE Plasma desktop, but this could just break your system (I’ve never done this myself, I don’t use Ubuntu).
So something like this to install the KDE Plasma desktop:
then upgrade to the latest KDE Plasma:
Perhaps try these steps in a virtual machine first.
Personally, I’d just backup everything you need, and would then do a clean install of a rolling distro - something like Arch Linux, or one of the more easy to install derivatives (like Manjaro KDE, or ArcoLinux, or EndeavorOS etc…). Then you’ll always have the latest stable Plasma desktop.
Alternatively, you could wait until Kubuntu 21.04 