[throwaway270925]

Yeah, 2016-2019 were severely cooling constrained unfortunately.

If you want to keep using it (maybe not as your main machine) there are some workarounds and fixes:

The simple software only way is to deactivate Turbo and/or HT. Less performance but also less power use meaning less heat. And checking gmail or browsing the web you probably wont notice much of a difference.

Or you can open it up and add thermal pads to your VRMs, finally giving them adequate cooling. Just dont touch the bottom of your macbook afterwards or rest it on your bed or couch, that thing can get hot!