Your issue may just be bad tires, swap the 2 front tires 1st, if no changes, then swap the back ones if it changes then that’s your problem. If not, then swap your 2 front hubs and bearings ( if it has front hubs )
Those old tires are really dry and probably shrunk one more than the other, just like Jim mention, if it was flat for a long time.
I personally never use a set of tires that are older than 1 or 2 months, if yours are older than a year, or 2, then toss them and install new ones, you’ll love your kart and now you’ll have a fresh starting point for set ups.
And yes, most chassis are repairable, unless the impact when wrecked was really hard. But I would try the things I suggested 1st, and then we’ll know what to do next. Please keep us posted and share with us what happened after your process of elimination. Good luck. Fast Freddy. ;)