This has also been my experience when I saw unreliable ZKs; they're sharing the OS, ZK, and maybe even some other services on the same disk, and sometimes they'

This has also been my experience when I saw unreliable ZKs; they're sharing the OS, ZK, and maybe even some other services on the same disk, and sometimes they're even running software RAID or something on top of that. I don't think teams who can't run ZK will have much luck running other distributed systems. (Maybe KRaft, if they're Kafka experts.) Most of the alternatives proposed here have been "let someone else run the hard part." (Which isn't a bad choice, but it's not technically a solution.)