What do you mean by "replicate in real time"? Do you mean that both servers would would be completely in sync at all times (i.e., that server B would have a "live" copy of what's on server A)? If so, then no, ZFS replication can't do that. The default configuration for pve-zsync syncs every 15 minutes, I believe. I'll leave to others to say what (if anything) would be a better solution.