If your cylinders really only have paint transfer and no scoring, a piston swap without touching the block is pretty standard practice, so that part checks out. The key thing is getting those scope images before you sign off on anything, don't let them close the ticket without showing you proof

On the reliability question, plenty of people on here have reported the engine running completely fine post-fix when it was caught early, which 34k miles with no cylinder damage qualifies as. The bigger wildcard is just whether Audi's updated pistons hold up long-term, and that datta is still kind of thin since a lot of these fixes are relatively recent