iOS doesn't give developers access to other apps' notifications, AFAIK. I'm not an iOS developer though - maybe someone with more knowledge can chime in.
There's an API for notification mirroring, but only in the EU. As you can guess this is a "deprivileging Apple Watch" thing. So there's no generic "filter notifications" ability, it's ONLY for sending notifications to a connected non-Apple smartwatch.
kmeisthax|1 month ago