The ground work he made himself. THere was no need to go that crazy in transfer market if you already have players in that spot and he does not have good pedigree in handling this kind of team. His tactical and man managment has been bad. Should have waited few years before making the jump.
Tuchel can be good for Chelsea, dont understand the hate on it. PSG was too much for him and all structure + players are hard to handle for any coach. He played good football in previous clubs. We have several German managers showing much better tactical awarnes and being suitable for PL.
Think he is bretty flexible with tactics so it will be intresting to see how things play out and who will be sold in summer. Think their midfield needs a bit of overhaul.
But anyway he is better than Lampard so there is that.