Yeah, this isn’t that bad. It’s just a suggestion after running an apt upgrade. NPM has similar plugs which I don’t find too annoying.
In fact its not even as intrusive as NPM’s funding requests, as it is only 2 lines of text, plus it looks like Ubuntu Pro is free for personal use.
They intentionally removed this feature years ago. It was possible to reenable via a dconf setting for a while but I believe that was also eventually removed.
So annoying.