Newbie here and need advice in implementing mongodb high availability

Details:
1) Multisite (AZ1 and AZ1)
2) AZ1 (Primary, Secondary), AZ2 (Secondary, Secondary), AZ2 (Arbiter)

With this setup, AZ2(Arbiter) would be a single point of failure because it doesn't have any backup server.

Revise setup:
1) Multisite (AZ1 and AZ1)
2) AZ1 (Primary, Secondary, Arbiter), AZ2 (Secondary, Secondary, Secondary), AZ2 (Arbiter)

Would the revised setup be feasible? Can Primary & Secondary have multiple entries of arbiter?

Or is advisable to have a setup without an arbiter like this (AZ1 (Primary, Secondary), AZ2 (Secondary, Secondary, Secondary) ?