Thanks to everyone on my previous post. I have since added a 120mm fan over my dimms (and secured it in the most janky way imaginable). Managed to get 6400 cl28 stable on my 9850x3d with these timings. VSOC is reported wrong in ZenTimings, I manually set it to 1.25v and confirmed it within my hwinfo sensor.
I'm willing to bet the memory controllers on the 9850x3d silicon is prolly a little more robust and more of these chips can sustain 3200mhz UCLK at a reasonable SOC or I just got lucky.
I ran 3 hours of absolut anta777 and an hour of vt3 (while listening to music) and got no signs to suggest the fclk is struggling (I managed to get 2167mhz stable at 6200 cl28, haven't tried to push further).
I did have GDM enabled, I might try to disable it and see if I can stabilize since so far no configuration I've tried has produced instability or failed a stress test. I really don't know if this is worth it since I'm not chasing benchmark scores.
If yall have any ideas on where I can reduce voltage or improve timings that are very likely to maintain stability I'm all ears but I'm pretty happy with this configuration. I'll update the post w/ my Aida latency tests in safe mode with latency killer off.