We are fortunate to have a trainer who is also a cyclist for my son. If I had to choose I'd go trainer over cycling coach and make sure you tune them in on how the bike works. Per your post - you need the motivation - a trainer will do that. You need to do the exercise correctly.
A cycling coach helps too, but from your description - the trainer is more what you are describing. Maybe make sure from a coach/bike shop you are fit right on the bike and ride correctly, but assuming you do, trainer tend to be more motivational and into your physical development.

DON'T mix advice, add more workouts etc. . I've see too many do what a trainer says, then do what a coach says (and the two don't know the other exists) then add their own and get fried. Follow/coordinate your program so everything you do is part of the overall program.
Right now - my son rides only 2-3 times a week and is in the gym 3X a week. As his trainer is his coach, he makes sure 2 rides are zone 2 and makes him take it easy so he reduces injury/burn-out/sickness risk.