Midgame doldrums

I just got the 'Raid the Storehouse' mission and it is a 4 difficulty mission where I have only done 3 difficulty missions previously. Realized I would have to do some pokemon training to progress and the interest to play just kinda evaporated.

My highest level character is 10 iirc and while I still enjoy the fights they're starting to get incredibly samey. Is there any midgame changeup or end stuff that is worth toughing through a training montage and more procedural missions to get to? Just from the mission difficult steps I assume I'm sorta halfway through but I have no idea.

I do think the combat system in the game is enjoyable but the entire overworld structure and repetitive missions isn't to my liking.