It’s your third car so i would rebuild the engine. You have some mechanical experience so have the tools mostly?
Once out of the car the strip and rebuild is much easier and more satisfying that anything else on a car as you have space to work. No dirt or rusty nuts. The inside of and engine is a delight compared to all the shite outside it🙂
Don’t bother with bore micrometers, just get the block rebored and the engineer will tell you what oversize piston you need.
Similarly, you can get the crank checked for a fee and see if it needs a re grind.
I used to rebuild Ducati single engines and restore complete bikes. The engine rebuild was always the most enjoyable part of the process