> You shouldn’t be receiving reactions to posts that you are simply tagged in.
Agree.
But depends on what you mean with "tagged". Explicit tag with @ should always be honoured, with the exception of blocked users.
If you refer to the "p" tag of the specs I double agree, I suspect clients use this to fire the notifications, while I suggest to focus the events and get the relations with the authors.
This fixes the "bad behaviour" of stuffing pub keys of every post in a thread.
NIP-10 doesn't seem to address the reply of reply case: https://github.com/nostr-protocol/nips/blob/master/10.md#the-p-tag