Kernel Power 41 is just whenever there is an unexpected shutdown IIRC. I was wondering if it might show something more helpful like display driver crash or anything helpful.
I had that combo and had three total incidents on 5008 (with 0 on 4207). The first two were at default settings (basically, except fan speed) with ram at 2666MT/s where the computer froze with Firefox open. I reinstalled the drivers for chipset, audio and my gpu and didn't seem to have a problem after that, except one situation where my USB devices turned off. That was with my ram OC applied and I think was actually due to slightly too low SOC voltage.
Is this Windows 1903? Sometimes updates do not respect the installed drivers, or can conflict with drivers.
I got an X370-F on the cheap and so I don't have the B350-F any longer, so I can't speak specifically on the newest two bioses. 5216 just came out.
If it doesn't seem to get better, might have to run memtest86 or the equivalent to make sure there isn't a ram problem. If that passes, might have to give 5216 a go (or think about downgrading, but that has some risks since you have to use afuefi or the like).