incipient burnout

[MeeLee]

I assume you don't play and fold at the same time?
If not, all it takes is reenabling the settings in Bios, and boot. It's an extra step, but may be a good solution for folding?
A Ryzen of this caliber needs a very good Noctua cooler, or a closed loop water cooling with at least 2x 120mm fans.
You may also want to run your case open, for better cooling (while folding).
Other things you can do, is reverse your PSU (by having it suck hot air from the case, out in the back (rather than suck in room temperature air).
PSUs can very easily offload the heat your case fans are dealing with.
You can also use tape and some cardboard, to create ducting (to rout hot air away, or channel cool air).
It's possible to get 5C cooler by doing just that.
Imagine you're preventing the hot air, from being re-inserted in the air intake (on CPU or GPU); and help it find it's way to the case's back.
It's trial and error to find the best workable solution, but costs next to nothing (just some old used cardboard, scissors, and a roll of regular old plastic tape).

AMD CPUs are tested up to 120C, at which point they just melt, explode, or error out.
They have a cutoff at ~100-105C (at which they just shut off, or reboot) in order to save the CPU.
They also gradually reduce performance depending on the temperature reading (if temps increase, voltage decreases, and thus performance decreases slightly).
If your temps are 95C and up, your CPU may only be running at it's limp mode frequency (could be 800Mhz, or 1,2Ghz... depending on what model), and you won't be able to do a whole lot with it.
Such cases are rare, and only when the heat sink is clogged, or too small for the CPU.

Even at 75C the frequency drops by a few 100Mhz over running it stone cold (50C or below).
I try to run my GPUs at below 65C, but occasionally they surpass 75C.
Some of my CPUs run at 65C, but some also run at 85C; which is pretty hot.

You will more than likely blow the motherboard's VRMs, or capacitors, than destroy your CPU from running it below 90C.
Your CPU lifetime even at 95C should be well over 4 years of 24/7 pegged at 100% compute; well beyond the time you'll want to keep it, if you are serious about folding (or gaming).
At 75C, I guess it'll be hard to wear out the CPU below 6-7 years of 100% load, 24/7 usage.

Performance wise, having a CPU run with PBO on (4,1Ghz) or PBO off (3,5Ghz), would make little difference.
Most games depend on the GPU to provide fluid framerates.
The CPU, for most games, will be fast enough. You may notice a few FPS drop, like 70 FPS instead of 75 FPS, but that shouldn't really be noticeable.
For folding, it matters more having more cores work, than have less cores work at a higher frequency.
A frequency drop of 10% doesn't really relate to 10% slower work done.