Why does my MacBook 15 inch 2016 keep restarting?

Sadly, your logic board either still has a problem, or one of your Thunderbolt port assemblies has a short.

Carefully disconnect the thunderbolt port assembly one side at a time (using the working side for your power)

You also may want to double check your power adapter is it an Apple unit of other? Are you using the original Apple USB-C cord? Not all USB chargers are the same! And the cords are likewise not all the same!

Some 3rd party chargers use different signals to monitor their charge rate and the cords wire gage on the power feeds may not be heavy enough to carry the higher current.

The last variable is the AC power its self! Make sure you are using a properly grounded outlet and ideally a surge suppressor (I have a nice two port unit for travel) or better yet a UPS while at home.