Advice on replacing top case but keeping the power button for Apple ID

Hello group, I have a 2017 Touch Bar, after apple screwed me once again on the recall I need to replace the keyboard and Touch Bar I have the flashing white light on the Touch Bar that drives me nuts and a couple of keys that don't work well.

I have replaced the battery but will replace again, thinking of buying a used top case. Previously, I have replaced an iPhone 6 battery and the home button so the phone would work. I'm sort of familiar but has anyone done so on the laptop I can't tell how hard it might be as there are no repair guides.

If anyone can offer any advice it would appreciated......