Most month-ends are slow for one reason: the same numbers get typed in more than once. Sales sit in one place, stock in another, and payments in a bank app. Someone spends the weekend matching them.
A system that records each sale once, and updates stock and the books at the same time, removes most of that work. Your accountant then reviews the result instead of rebuilding it.
Try this now: list the three reports you open at every month-end, and note which numbers you retype from one to another. That list is the work to remove first.