How long is it on for? Unless you’re turning it on for minutes at a time, I just can’t see how it would never have time to download things in the background.
The only way I can see this really happening is if you’ve a) got obscenely slow internet or b) have all networks listed as metered, which would indeed prevent automatic updates (unless you specify otherwise.)
Might be a good idea to dig into your settings, because the age of needing to babysit windows updates has been gone for years now.
Settings and internet are fine. I dunno what to tell you. Very frequently Windows update shows its head, like I’ll randomly want to restart my computer because I installed a piece of software that required it, and then it kicks off a long round updates when I just want to use my computer.
I still think having to leave it on and let it run in the background is still just addressing the symptoms. An update process should be way faster than that so that such a thing isn’t needed.