Unity on Linux: Unity Hub Downloads New Versions but Doesn't Install

Hi. Ubuntu Bionic Badger (18.04) Kernel 5.3.0 using Unity Hub (the only approved method of installing Unity on Linux that I am currently aware of, as the Unity install archives do not have Debian or any other form of package installers supported) to re-install Unity as my old installs disappeared for some reason. The blue loading bar at the top of the square where it has the Unity symbol and the version (plus notifications as to whether the version is experimental and/or LTS) under/in the Installs tab is complete but the square/tile/card containing aforementioned information is grayed out. I have been waiting for several hours twice now and it's still grayed out. Is it installing? Did it download? Why is there no status indicator at this stage? Did the previous status indicator get used up (the blue bar)? Do we need two?

Hmm.

Many questions.

So in any case, I'm not sure how to install Unity on Linux (again) so any help is much appreciated.