When Josh went to the Raiders he took with him a cast of Patriots' coaches from the offensive side of the ball. This in my opinion is why the offense is really hurting. So, who did he take and what were they in charge of.
Mick Lombardi was the Patriots receivers coach and many believed to be in the running for the offensive coordinators job in New England. Well, he became the offensive coordinator for the Raiders. Previous to coaching the receivers, Mick was an assistant quarterbacks coach.
Bo Hardegree served as the quality control/quarterbacks coach last year in New England. He is now the quarterbacks coach in Vegas. If you read hisbio you'll see that he is a former quarterback who is credited with the improved play of Sam Darnold his second year in the league.
In my opinion, losing that group of coaches is a big reason why the Patriots are struggling. If we had a parallel universe where Josh didn't take these guys with him, the offense would look a lot better
Check out a recent post I made- DO THE PATRIOTS WIN GAMES WITHOUT A GAME CHANGING DEFENSIVE OR SPECIAL TEAMS PLAY?