This is why NIP-114 is mentioned, it's a simple proto to return only ids, then client can decide what it wants to fetch.
FYI, I think full Negentropy is way too complicated. I have been testing a similar, but simpler sync scheme and I think it solves most of the need https://github.com/nostr-protocol/nips/pull/826
Discussion
I can't find 114. Is there a text somewhere? I am trying to sync 200K events at least once a day. I am not sure if the id-only version would work but happy to test.
Made a pull request to the nips repo https://github.com/nostr-protocol/nips/pull/1027