I love your idea of rewarding top zappers for generosity, sharing, support. But have you thought about how to avoid the problem of "the richest get to be the loudest"?
I can't claim to have answers, but how about a # of sats threshold that qualifies as a "top reply" and then no upper limit in that category but they're not sorted by sats zapped? The rest go below the "top". Perhaps each user can specify what they consider that # should be for their account. (For nostr:npub1cn4t4cd78nm900qc2hhqte5aa8c9njm6qkfzw95tszufwcwtcnsq7g3vle it may have to be a lot, for me - like 10 lol).