MRP only schedules two very limited kinds of jobs… firmed but unscheduled (meaning jobs someone firmed up after the last MRP run but didn’t release or schedule), and UNFIRM job suggestions it creates. MRP does not touch any job that is already scheduled.
Therefore MRP alone is not going to solve any problems with your EXISTING jobs.
It sounds like your routings, production standards, resource groups, and the rest of the foundational stuff is pretty accurate, which is the first biggest headache. You’re already using Finite Scheduling, so you have a pretty good idea of the ride you’ve signed up for.
I heartily recommend checking out this post Global Scheduling by @jtownsend where he describes VERY SUCCINTLY the steps he takes and why he takes them. And then there is the sheer indescribable joy of the Scheduling Technical Reference Manual.
I’ll even upgrade my previous “Can it work for you? Probably”. to Almost Certainly. You have a great beginning, and we’re all here to help!