Thanks for the info, root crop farming is pretty neat. I would have liked to use Grimme equipment a bit more but the base game vehicles they have are just terrible! Probably would've taken me 10x longer to harvest everything with them. The holmer mod I used is for either sugar beet or potato even though you are right it's meant for sugar beets in actual farming.
If you don't want to have those hills blocking some of the potatoes just make it flatter and those problems go away yes it will take a lot of money but in my experience it is worth it
Good call! Thats definitely a solution, but I also think it was a planter issue since the base game ones didn't have any trouble with the hills. But I had so many potatoes in storage I didn't mind a few bare spots here and there