Maybe someone with machining experience can fix it. On my E39 M5, I had this same issue with oil leak coming from drain plug so I elected to remove the oil pan and sent it to a guy in Wyoming or Wisconsin, for his work to repair this. I am sure he drilled the hole much bigger to fit/press in a steel bushing so that it would not strip ever again by over tightening.
See post #22.
https://www.m5board.com/vbulletin/e3...-though-2.html