I’m a garmin user that moved from android to iPhone several years ago. I really miss the ability to filter notifications that hit the watch, which is still missing on garmin iOS software. I don’t think it’s a restricted api problem, as other smartwatches can filter notifications

In IOS, you can not get list of installed app, so you can not do notif filter purely from app.

Notif is delivered by OS itself, through ANCS.