The fact that the team always has very inconsistent performance in two halves indicates:
either, 1) the manager and his assistants do not enough variations in tactics or they are simply not good enough to make tactical changes.
or, 2) the players do not yet understand the manager's tactical system and fit themselves in accordingly.
or, 3) the manager does not have bench depth
My own observation is 2) and 3).
IMO it is only fair to give RDM a good finisher, other 2-3 ins, and at least 15 games, maybe till Xmas time.
If RDM gets the players he wants, but fail to get at least 6-7 wins in the next 15 games, the honeymoon time between Xia and RDM will very likely be over.