It might be easier doing it with CTR in the end. Have you tried it yet?
ClockTuner v2.1 for Ryzen (CTR) Guide - Introduction (guru3d.com)
Of course you'd want to use the suggested settings that are in the CTR requirements section in the above guide.
Have you stress tested with CoreCycler?
Release v0.8.2.4 · sp00n/corecycler · GitHub
The above works good to find the weaker core(s) from my testing. Of course you'd need to switch from the all core - offset to individual core offsets. You can still start at -20 if wanted.
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Both the above apps and uEFI have been updated from the last time I booted up my 5600x backup rig so I'll be playing around with both today.