If you possess a Pawn and try to rotate it in any direction, you’ll be limited to 90 degrees in any direction. It’s a bug acknowledged by Unreal developers.
However, if you do the rotation in your custom PlayerController blueprint, you can freely rotate 360 degrees without limit. The rotation values (roll, yaw, pitch) can even exceed 360 degrees and it’ll work perfectly. So rotate the actor from within your PlayerController blueprint instead of your individual Pawn blueprint.