Applied through a referral.

OA was skipped as I had other offers and wanted to close fast.
Algo round was 2 questions - a bit harder than medium.
System design started out as an lld problem for a parking lot management system but he later made me scale the system applying system design concepts and covered api, db etc.
There was a tech round with lots of problems around java like immutable, wait notify semantics, happens before relationship, completable future, a problem on concurrency, some db concepts like normalisation, isolation levels etc.
Behavioral round with typical questions about motovation to join zeta and past work situations discussion.

Got a hire call the next day. 🙂