So, in the everlasting adventure of replacing my house’s doors, I’ve found some questionable engineering “solutions”, most of which I’ve managed to fix, but I now have a couple of door frames which’re upvto 4mm out of true. Should I belt sand or plane them flat?

what i do is plant another bead say a door stop bead or 2 inch pencil round on framme abutting door, this seals the gap quite well and once painted is not noticeable, do both sides of frame and top.

Or fit door so it closes tight against door bead on latch side by moving a hinge out a bit.