Never used a GB mobo but you can try to change the load line calibration switching between presets.
Also i had the opposite bad experience with with B760 and 13600kf. Abnormal power draw and voltage spikes. Voltage fine tuning didn’t solved the problem.
Only solution was to switch to z690/z790.
Try to monitor the p-core frequencies, if they goes under 5.1GHz during test the cpu is not getting enough Watts or Volts.
Just get 192+ GB DDR5 Ram. 1 GB per tab should be fine.