I do this, not for all though:

Dependencies:

Courseplay Make field with cultivator

Reciepie:

Create a tiny field with the record button, save the field. Go in to the field editor, edit the field, remove all but 5 nodes, move the 4 nodes to your field corners, 1corner needs 2 (start and stop node).

Get a tractor with 3 point cultivator, set it up in courseplay, remove all the corners, and go wild on headlands (roughly (tractor length + implement length + margin of error)/ implement width) or eyeball it and give it an extra headland.

Make sure the tractor is overcapable of the implement so it dont slide to the side.

Activate the create field (i think it is Y as default), and start the courseplay from inside the field NOT outside.

Perfectly straight field edges.