Samsung A53 5G SM-A536F switching off intermittently

[mixmax]

Samsung A53 5G SM-A536F dropped, screen cracked. replaced. Phone works now, but switching off intermittently. It doesn't turn on at all if phone is assembled and all screws are in. When motherboard is loose, it works. I suspect, there is a crack in the MB or pin on some component. The question is:
is repair attempt feasible and what is the best way to do it?

[rogfanther]

Well, you would need to carefully flex the boart to find the region where curving makes the phone start/stop working. But if the problem is with the soldering of some bga component, it is harder to diagnostic or solve.

[mixmax]

After a while, I found out that similar MB issues are common with the Samsung A53 model. Local repair shop gifted to me three bad A53 motherboards to play with.

I will measure voltages and RTG values on each, then compare. What method/software for writing results down you recommend?