Hmmm ....
Greetings,
I doubt a 450m based board would have been my first choice, but that's what you've got.
There are 4 variants, we don't know which you have?
You are the second person in recent weeks who has posted about a problem with F50a (a beta BIOS) who is running a RavenRidge or Pinnacle Ridge CPU. I think sticking with F32, F40 or F41 might have been a better choice.
I don't see your memory on the QVL for your board? If not, this is another potential problem area for you to deal with.
I think the only way you are going to gain stability is to:
A. Consider downgrading your BIOS
B. Setting your memory timings and voltages manually
C. Using RAM on the QVL for your board
I understand you are frustrated, but some of the choices you have made might be influencing this. Sorry, cause these types of problems are never fun to deal with.