I got similar problem on 06 -01-2021. My macbook pro is 15 inch with touchbar,2016 model. after some research I was disheartened by reading many blogs where the logic board replacement solution was provided by apple and for many they had replaced their laptops. However after further research I could conclude that the problem lies in the firmwere update for touchbar which is not in sync with the latest catalina update so when the laptop restarts it cannot find the firmwere for touchbar. I believe some of the apple OS updates are not synched with the touchbar firmwere thats why this problem occurs. The supported firmwere patch is not reachable or is not available for the update from apple or we cannot download it due to network issues maybe some apple ports are blocked. I addressed this problem by logging in safe mode by pressing Left Shift Key during restart and then signing in to my apple account again and then installing the latest OS mac OS Big Sur version 11.1. which has enabled my touch bar again and also is not giving me any problems after reinstall. I believe this OS comes bundled with updated Touchbar Firmwere and thats how the problem is resolved. Hope you guys find this solution helpful cheers.