Sounds like a defective machine. I'm surprised Apple didn't just give them a new one after the 2nd or 3rd repair. That said, looking at the keyboard condition

Sounds like a defective machine. I'm surprised Apple didn't just give them a new one after the 2nd or 3rd repair. That said, looking at the keyboard condition makes me think it was in some pretty harsh conditions. My 2012 17" keys still look almost new. I've only had a single experience where I had to repair my Mac in ~8 laptops, which was my Apple M1 aAr that died from plugging in a third party USB-C adapter (multiple reports of this happening).