Seemingly random freezes are almost always down to one or more of: RAM, overheating, loose hardware, lack of power.
Cards can work themselves free over time. This is a known issue and why AGP and PCIe slots have clips.
Troubleshooting/debugging is a process of elimination, so if you follow a series of steps it narrows down the possible causes of the issue.
If you ignore a suggestion you leave that as a variable. If you ask for help then question the answer because it’s not the simple answer you want (“install this” or “make this specific configuration change”), then people aren’t going to bother giving any more help.
So, the first step is to ensure all of your hardware components are seated correctly.
Or, go back to SuSE and run it for the same length of time as Manjaro and see if the issues reoccur.