I really think they needed to do something to meaningfully change up the gameplay flow at Garreg Mach in Part 2. It's just not well-designed, with huge chunks of dead time you basically just waste on whatever instead of the focused, purposeful forward momentum of each Explore session trying to recruit characters or build Byleth's skills high enough to do so in Part 1.
Yeah I'll probably always have the the opinion that they should've cut the monastery part 2, or at least minimized the number of months you spend there.
At least if they don't wanna give you new activities or objectives.
Like that chapter before you attack Garreg Mach could've been enough.
Just a smaller war camp or something, with a kitchen, blacksmith and so on. Something to remind you that there's a war going on. To me the monastery just feel empty an lifeless in the timeskip :/