I heard around 15 flights were scheduled after midnight, in addition 35 delayed flights also landed after midnight, looking at 50+ aircraft landing there was no way this would be staffed for or even could be staffed just in case of delays.
I think this problem won’t be resolved any time soon, there is just not enough staff nor will airlines pay for more just in case.
However we are really talking Ryanair, I would rather fly with Jet2 if I was arriving back at Stansted 2330 onwards they have much better customer services and being self handling much easier to handle delayed aircraft.