I think you have to deal with the fact the manager played strong teams in the cups and wanted to win those cups. Hes the boss and he was right. Deal with that.
We played in every single available cup tie (including an FA Cup replay) to the middle of January and still got to third. Our collapse has coincided with not playing anywhere near the maximum amount of games with no FA Cup 4th round replay, no 5th round/replay, no LC Semi or final. Fewer games, worse results. Deal with that.
We had two wonderful weeks off of rest and still got dic ked at home by Liverpool who had played two matches in the intervening time. Deal with that.
As long as Ronald is manager next season well be having a go in the comps we're in, hopefully the Europa League. Boo hoo hoo lots of horrid football matches to play. Deal with that.