TPMs don't impede your ability to repair anything. Soldered ram is a hassle, but it's not any more malicious than soldered CPUs. It's a design choice, and tradeoffs had to be made.
It's suggested that many such devices might be stolen. But there will also be devices where the user forgot to wipe their data (or didn't know how); or devices that are only just damaged enough that you can't wipe the user data.
Probably an official Apple store can refurbish them somehow, but that is the NOBUS / EARN IT argument.
This kind of stuff shouldn't really theoretically have to affect repairability, but Apple seems to go out of their way to make sure that as much as possible gets bricked when you replace things.