It doesn't take much to make a battery pack safe to work with. Every EV I've seen has contactors on both battery terminals, as well as physical shunt that is removed before servicing, in case a contactor fails closed. There's usually also contactors within the battery, making it possible to work on the battery pack itself, without any unsafe voltage present.

It's no more difficult to make safe than household wiring, and DIYers work on it all the time.