I've done thousands of pull-ups with this style of pull-up bar and never had an issue. One of them left a black mark above the doorframe but it wiped off with a damp cloth.
If you're interested in something portable which you can set up outside, you might be interested in the Pull-up Mate. I have one (the second version with added support) and it's pretty sturdy.
That's fancier than the first one I had, which would screw tighter or looser with every pull (obv I oriented to screw tighter, but it cracked the door a bit (the landlord didn't notice though)). Hard to tell if this one will have the same issue. If your doors will take the over-door variety e.g. https://www.amazon.co.uk/Body-Sculpture-Total-Upper-Workout/dp/B003H9LK14/ you might find that more stable. Both will scuff up your doors a bit though.