I cant offer much more advice. I can bench y cruncher with A die on 12900k/2022 Apex but getting memtest/Karhu stable is another thing.
I found it is easier booting 7400, 7600 and 7800 than lower clocks.
I have a 13900k coming and hope that helps with these A die.
I can run 7000c30 with m die...