Dell Latitude 7490 powers on then off

I picked up 4 Latitude 7490's for $25 each from my local county surplus warehouse. I noticed 2 are from 2018 while 2 are from 2019. I got home and tested all of them and found the 2 from 2018 will power on then power of 2 seconds later. I see this seems to be a common issue with this model and want to know if there is a fix for it or if I would need to replace the motherboards on them. I can get motherboards on ebay for around $45 but something that bothers me is that the service tags won't match the systems.

Has anyone found a fix for these boards that are dead?

Is it worth getting replacement boards or should I take the good parts and make 2 good units out of these 4?

Is it at all possible to reprogram the service tags from the old boards or no?