Vintage Peugeot conversion help and tips please

....until i set to remove my cranks with a crank extractor. The main bolt doesn't screw all the way in to
the crank's thread and when i apply enough force, Only the thread fooks up!!!!
Now my crank arms' threads are torn and I still can't remove my crankset for BB maintenance

I'd either try to clean the mashed-up threads with soap and a toothbrush and then re-insert (trying to get it to thread further.

Or, I'd just look at the picture a few posts above and consider bashing shit out of the crank arm with a hammer. Could also heat the crank arm near the axle in preparation if it's seized. There's also sometimes an option of sticking a large blade screwdriver between the back of the crank arm (near the axle) and the face of the bottom bracket and lockring. If you hold the screwdriver vertically, you can hammer it into this gap, prising the crank arm off. Good luck!