Triarius

Could you make sure the molex adapters are not running on the same line?

There are seperate lines for 12V and other voltages which could be heavily affecting your GPU.

The CPU (65W) + GPU (185W) + other components ( extreme RGB worst case sceneario ) [30W] means that your usage is usually under 250 W or so even under long periods of gaming.

When it crashes can you check if there's a mother board light that's generally blue?
This light usually means that the system doesnt have the required power and has entered power saving mode. Which also means that the PSU is .... fried.

Come back to me when this doesnt help or it helps.
If it doesn't help I could get you back on track as it helps narrow my understanding of whats going on in that poor rig.

 

generally BCLK is a Z series exclusive feature as well, so a Z390 motherboard and an 8700 would be able to OC, but not a B360 board and an 8700K.
 
also, @Triarius a B250 motherboard does NOT support an i7 8700k, 200 series chipsets only support 6XXX and 7XXX processors. If you want an i7 8700, get a 300 series chipset like a B360 motherboard or H370. If you want to OC, get an i7 8700K and Z370 motherboard.
thanks to my tiny resolution I'm currently using I saw the 6 as an 8

You could see if there is a bios that still supports BLCK overclocking, but that is not conventional overclocking (Which - as said above - is not possible).
 
It is also somewhat unstable, since I don't think you can increase voltage..
 
I wouldn't bother with that, to be honest.

Intel's non Z motherboards never support overclocking. It just means it can run it, not overclock it