Some things that come to mind:
5600 is a lot faster than 2600, so GPU and everything else runs much faster too, which puts more stress on everything and more heat is produced.
Since I doubt you have plenty of extra components laying around, have to think what can be done to find out where the issue is.
If you run Cinebench R23 (select advanced benchmark and then 30 minutes minimum test duration), you can stress CPU without stressing GPU (nor PSU too much) to see if that and memory are stable. This is not exactly a memory stability test, but if there are serious memory issues, they should crash the software too.
Second, run something that stresses GPU heavily, but not necessarily CPU that much. Maybe Heaven benchmark maybe 10 times or more (can't remember if there is setting to let it loop by itself). This should show if there is a problem with GPU.
While 95C should be ok as a junction temp, never know how accurate readings are. I would try running with side panel open to reduce temperatures so see if that is an issue. It temp reading is still 95C, try setting an fps cap to game to reduce how heavily GPU is used to see if something changes and offers any clue.
If that does nothing, return settings and try running the machine with two memory sticks only and if problem continues, remove used sticks and install the other two. If problem continues, try running with two sticks, XMP disabled.
If problems still occur, I would suspect PSU before motherboard.
While not common, it can of course be the CPU, but without testing and trying, it is just guessing.
