I have the same problem with my 2016 Macbook pro touchbar. I replace the touchbar with the new one but from the 3rd party sparepart. After replacing its going fine and then the macbook get new update mac os big sur but when its updating the power is low and i forgot to charge the macbook because i suddenly fell asleep. In that morning i turn on my mac and thats issue is comming . I try everything reinstalling , clean ssd and its still doesn't work