From what I’ve heard, this is actually a problem with the exposed OS level api’s provided by Apple. Other manufacturers have solved this with on device workarounds. Doesn’t make it better though. I resorted to only the system only notifications (Phone, Texts).

As an end user, all I really care about is that the watch doesn't buzz every single time my long-winded colleague hits <enter> on slack, but that I do see slack notifications when I'm able to look at my phone. And I always want to see my wife's texts on my wrist...

Whether that filtering is in the app, in the OS, or on the watch is not important to me.