@MarkA had any crashes so far?
I've been reading up on this for most of the evening and here's what i've learnt. The Ryzen CPUs have a power state called C6 which allows them to disable individual cores when not in use and drop the CPU voltage all the way down as far as required, even to zero (!) if necessary (what's the point, it's basically off?).
When the CPU drops into this state it seems that it's not applying enough voltage to keep itself alive, which means there's either a bug in the CPU itself or it's not stable at that certain clock, with those cores disabled, at that voltage, which means a binning issue.
Either way, i've found reports of people with first gen Ryzen processors getting the same issues back in 2018. And there are lots of them. So AMD have completely dropped the ball here - this should have been addressed at BIOS level years ago. The fact that it's persisted through 1000, 2000, 3000, and now 5000 series is absolutely appalling.
The suggestions vary wildly but most get success from disabling C-States, which stops the CPU going into C6. But it also stops it leaving C0, which means you will never drop below stock voltage. This has heat and power draw implications.
Hope that helps.