Not OP, but managed a ~1tb Postgres install for years. You should use something like pgbackrest or barman to help with both replication (replicas can pull WAL f

Not OP, but managed a ~1tb Postgres install for years. You should use something like pgbackrest or barman to help with both replication (replicas can pull WAL from your backups when catching up), backups, and failovers. At least for pgbackrest, set up a spool directory which allows async wal push / fetch.