It sounds a bit like it, so at least your garage does seem to know about these engines and what SEAT/VW Group did to improve/repair/update them.
I'm sure that there is a list of what normally gets done to these engine when they have failed, somewhere either in this forum or on a VW forum, seems like there was a few different "chain kits" that addressed some problems, but I'd hope that the newest versions and so part numbers, of these kits would be the best answer to sorting that engine out - along with the newer pistons and rings. I have no personal experience of these engines, but, I think that I read that because VW Group "sorted out" the piston design, if your car needed an original piston replaced, all 4 pistons would need to get replaced due in part to them being a different weight - and if these newer design of pistons are so much better, it makes no sense just to replace a single piston and keep repeating that as time goes on until all 4 have failed and been replaced with new ones.
Good Luck, it sounds like your engine is getting updated/repaired in the proper way!