I was under the impression that they recently fixed the limited set of notifications problem, though I'm having trouble finding the source at the moment.
They added a bunch more apps — there's maybe 40 or 50 now. The best news is that they're clearly aware that this is an issue and will presumably be adding more in the future. Some of my important apps are still missing, though they've added some important ones (Facetime, Slack, Skype).
Thanks for pointing this out!
1: https://apps.apple.com/us/app/fossil-hybrid-smartwatches/id1...