The conclusion that I've reached is that the whole lucene model for logs is kind of outdated. Why am I tuning Java GC params to run "grep foo /logs". I think computers today can do fine with sharded flat files, a minimal index ("which node contains logs from pod foo-2387438-2384738 at 12:34AM"), and then just scale horizontally over (log messages, searches).
I hope my friends over at Tailscale are doing that and I can just move off ES entirely ;)