Okay since you are saying that in a older AMD Driver version your PC with dual Displays works fine without crashing but as soon as you update the AMD driver and use the second display it crashes.
By your post it clearly seems like a AMD Driver issue. It is possible the latest AMD Driver has some new feature that is not fully supported by your second Display thus crashing.
Also since your second Display using 144hz DP might be a reason for problems.
Try connecting just the 144hz Display and see if it crashes with the latest AMD driver installed. If it does then you would need to troubleshoot to find out why it is crashing only with the 144hz display connected.
If it doesn't crash, now connect your 75hz Display and see if the same thing occurs.
Since your PC works fine with an older AMD driver version installed would rule out PSU being under powered.
I would open a AMD SUPPORT TICKET and see what they suggest from here: https://www.amd.com/en/forms/contact-us/support.html
NOTE: What are the exact Error messages or BSOD errors you are getting?