You don't need to be making changes to the CPU voltage. The CPU voltage should be automatically controlled by Auto setting and you should LEAVE it that way. Unless you are an experienced overclocker and you know what you are doing AND why, there is no reason, at all, ever, to make changes to the CPU core voltage.
Set it back to auto and then don't mess with it again.
As far as the CPU temperature, what was the ACTUAL temperature it was maxing out at? It doesn't matter if it goes up and down by ten degrees, that's entirely normal. Ryzen CPUs (All CPUs really, but Ryzen especially) are VERY "cyclic" in that they cycle up and down quite a lot, especially with the stock cooler. Right up front you need to know that the stock coolers aren't very good, in fact, I say they are not good enough for any CPU they come with. Using a Wraith cooler meant for a CPU one tier up, is ok, but using the coolers they come with is just not satisfactory except maybe on the Ryzen 3 models.
I always recommend getting a better cooler for any Ryzen 5, 7 or 9 CPU.
For the Windows power plan settings, you NEED to go to the AMD website, get the latest chipset driver for your motherboard chipset version (B450, X470, X570, etc.) and install it. Then, go into the Windows power options and set the plan to Ryzen balanced. That is how 99% of Ryzen platforms should be configured.
If you're going to configure the power plan manually, which I don't recommend on Ryzen, then you should set it to the performance plan but set the minimum processor power state to 8% and make sure the max processor power state is set to 100%. Using Ryzen balanced is a much wiser idea though.
Also, in the BIOS, make sure you have ALL of these set as follows:
Cool N Quiet - Enabled (If this setting is not available in your BIOS, just worry about the rest)
Core CPPC - Enabled
CPPC preferred cores - Enabled
Advanced/Global C-states - Enabled
Precision boost overdrive (PBO/PBO2) - Disabled (Unless you have high end cooling installed. Also, standard boost profiles like Precision boost (Non-overdrive) and XFR2 should be left enabled.)