To be fair, a lot of people use ZK wrong, then complaint about it.
For example, if you use it like a general purpose KV store like Redis, you'll have a bad time.
Another often encountered mistake is people, thinking it doesn't need to store much data, deploy ZK to a server with slow disk/network. Big mistake, as every write to ZK need to be broadcasted and synced to disk, a bottle-neck in disk and network IOPS will kill your ensembles.
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.)
For example, if you use it like a general purpose KV store like Redis, you'll have a bad time.
Another often encountered mistake is people, thinking it doesn't need to store much data, deploy ZK to a server with slow disk/network. Big mistake, as every write to ZK need to be broadcasted and synced to disk, a bottle-neck in disk and network IOPS will kill your ensembles.