Question PC randomly shuts down, PSU replaced but to no avail

Sep 14, 2022
I have had some problems with my PC as to regarding on random shut downs that occur, a week ago my PC has been shutting down randomly and when it shuts down, I cannot turn it on back unless I wait for 10-20 minutes or plug it out and in and then also wait, and since that looked like a PSU failure (that was also very cheap to begin with) I replaced my LC Power 650W 80+ Bronze with BeQuiet! 750W 80+ Gold (store only had the 750W version, I know its a bit of an overkill) and the PC stayed turned on overnight and the day after with no problems, and today, 2 days after, I have had experienced 2 random shut downs, my only suspect is the motherboard, GIGABYTE B450 Aorus Elite, I have also noticed whenever the PC turns on sometimes GPU fans from my Gainward RTX 2060 SUPER spin at max speed and I can't control them in it's software, whenever they spin at max speed, PC will turn off randomly in 20-30 minutes since booting up, if they spin normally, PC will work okay and there will be no shut downs, don't know how is that connected but it is a small detail I picked up.
My other components are Ryzen 5 3600 CPU, Geil EVO Spear 3200mhz ram 2x8GB (I ran them individually and problem still persisted) and one Kingston NVME SSD and one normal SATA Kingston SSD. I have tried taking out CMOS battery, unfortunately there is no diagnostics in BIOS, event viewer just says critical power issue, I have not updated BIOS since I am scared if it turns off randomly my motherboard would be bricked, I turned off fast startup in windows, fast boot is off in BIOS too, temps are good, I always monitor them.
It all points to the motherboard but I don't have a spare one to test it out so I would kindly appreciate any of your opinions and suggestions.