I think both clubs are in disarray in their own ways. Both have great managers but not idea players. United have good players on paper but who seem to have really poor attitudes and undermine the manager eventually.
Chelsea have spent a lot of money but have a completely new squad who have had little time together and are very raw.
It’s easy to say “Chelsea should because they spent 1bn”. But I am talking about their current squads, manager, board, situation etc
Both are not going to win any sooner. But, I would say Chelsea, United problems are much deeper and with Chelsea team improving they are challenge for title in couple of year.