Kafka can sustain sub 20ms at millions or even billions per second scale. Processing time delays is bad consumer code and partition design smell. Aka , your consumer shouldnt depend on a slower resource within an ordering domain. This can also be mitigated with an async consumer

These sound like consumer issues to me.

Kafka had been extremely reliable with latency, even under load in my experience.

If you’ve got badly lagging consumers that are trying to read from very old points in the topic while everyone else is at the head, you’ll definitely see some increased resource usage, but again, that’s mostly a consumer issue, and I’ve need seen performance degrades that much.

If you're concerned about latency you might want to consider zeromq. Stream processing doesn't really have a time expectation to it.