Too bad you dont have the K version of the CPU...
You would likely Benefit the most from a SINGLE GPU upgrade. GTX1060/1070 would be good
Next would be
2x8GB ram (or add 2x4gb same as you have now, to end with 16gb)
Larger SSD hard drive
Check through your ACCESSIBILITY options, there was an extension on Win10 upgrade through that section of your windows. Should upgrade if still possible.