i think most of you is over optimistic about it, the only thing that is good is that it has repaceble ram and TB3. 64GB of ram, should support 128 GB with todays impressive. 2012 macs supported 32 GB.
The problem tend to be the Cirrus chip, remove underfill and reflow. If that failed replace chip. Had this issue on 3x820-3476 water damaged and it was the chip every time. It worked with a reflow 1th board.
If you came here and have a MacBook air with fan running it can be the following: Bad trackpad/keyboard or PO Flex/DC inboard If you have error with CPU and PCH die thermal sensor being at 128 Celcius (program: HW sensors) you have a bad/waterdmg fan, replace it. If you don't have a new fan remove the fan power it up and see if CPU and PCH Die temp is back (keep in mind to maybe turn off auto startup apps so it won't run to hot when power up without fan). If this didn't fix the problem you have problem with CPU thermal IC's or bad trace from CPU_THRMTRIP_3V3 resistor in to SMC.
Try remove the clock battery and leave it outside and have power cord disconnected for 10 sec. That solved the issue with mine, I can't have clock battery in it otherwise it won't start. And if it goes to sleep or I power it off, I have to remove power cord again for 10 sec to get it to start.