if it is safe for an untrained individual to do so.

Remove this part and I agree. If you don't know how to repair it yourself, you can always go to an independent repair shop. But if manufacturers don't have to make parts available, you are at the mercy of the manufacturer.

So make the parts available and publish schematics, and those who want to can attempt the repair themselves, and those who don't can take it to a repair shop.

Manufacturers use the "but it's dangerous!" excuse to lock people into their ecosystem and/or support planned obsolescence. That needs to end.

During the early days of cell phones, replaceable batteries was the norm, not the exception, and it was as complicated to perform as your TV remote. No need for training. In these modern days, you may want to turn off your phone cleanly before proceeding, but that's pretty much it!

Let's not even talk about the early handheld game sets: the GameBoy (Nintendo) and GameGear (Sega), that were using regular disposable batteries (rechargeable ones were recommended though!).

Vendors have made our devices complicated to repair to lower costs and later to make our smartphones water resistant. They started off being easy to disassemble and re-assemble.