[HO Kenny]

Without knowing where true DTC is, you don’t know if your timing marks on your harmonic balancer are correct, you can’t know that your cam to crank timing is correct, EVEN NOW! Using a degree wheel will not help if you don’t know true TDC.
If you can’t use a timing light to set a known starting point you cannot do proper troubleshooting.
Unless there is something wrong with the camshaft or timing chain set, or the way it was installed, switching them won’t solve the problem.
Chasing our own tails is only fun for dogs!
It’s possible, but not likely, you have multiple problems. The previous owner may have put the cam timing out on purpose to mitigate another problem.