This thread is a godsend honestly. When I search for Unraid and Home Assistant all results are from 2 years ago.
Anyway, I used to have digiblur's hassio supervisor running and when it ran, it was great. Like you, I've had to restart it and add the letter in the description to get it working again. Sometimes I'd have to completely reinstall, and that got monotonous so about 3 months ago I deleted it all and every sensor box and LED strip sat dormant. Today I have some time so I'm trying to get it running on Unraid again to no avail. Simply adding the hassio_supervisor docker doesn't load the home assistant landing page. Logs show supervisor as running normally with no errors, yet I don't have an accessible page. I get an "err_connection_refused" error, and in searching that I get results from 2017.
I deleted everything and installed the "home_assistant_core" docker image and had a usable home assistant instance. However, again like you, I was missing the addon store. I installed digiblur's "hassio_supervisor" along side the home assistant core image and restarted the docker, restarted the array, restarted the machine, and still no addon store.
That all brought me to your thread. I don't really understand how to get this working like it used to. My next step is to try a VM and see if that goes anywhere. I'll report back if it works.