Question 6800 xt - PSU related problem?

[kurban2213]

Rig:
->AMD R5 7500F
- >MSI B650m P
- >RTX 4060 TI VENTUS 2X ---> changed to 6800XT
- >ADATA 1TB Legend 850 Lite NVMe
->GSKILL 16GB (1x16GB) Ripjaws S5 Siyah DDR5 5600MHz CL36 1.2V
->XIGMATEK LIQUID KILLER X240 SİYAH 1800RPM ARGB AM5
->XIGMATEK LUX G 4x120mm ARGB FANS -> X-POWER 750 80 PLUS POWER SUPPLY --> This is DODGY
Bought this rig pre installed, it was fine, was overclocked 7500f to 5.3 and tuned 4060ti, cuz i bought new monitor(lg 27gr75q 2k) need more vram bought ASUS TUF 6800 XT 3 slot behemoth than things started to go wrong: after putting on 6800 xt there is no crash no nothing benchmarks passes fine (furmark, userbench vram tests OCCT and etc) pc can idle like forever but when i play gta 5 pc randomly turns off after like 10 to 30 mins later blackscreen i have to restart pc, but when i play last of us game starts but after 2 mins pc turns off, and waits at black screen i have to turn it off and on to get me screen, my suspicion is on PSU, i couldn't even find product on internet, but from what i gathered PSU of this branding delivers like 100w loss (which it works like 650w bronze psu)
https://ibb.co/Lpkdgsd here is what it says on psu

 

[--SID--]

X-POWER 750 80 PLUS POWER SUPPLY

This is your problem. It's a 500w PSU with terrible voltage regulation and it's missing essential protections.

 

[kurban2213]

This is your problem. It's a 500w PSU with terrible voltage regulation and it's missing essential protections.

https://ibb.co/Lpkdgsd - here is what it says on psu

 

[DSzymborski]

Yeah, that's a frightening PSU.