Question PC booting (post-ing) only extremely rarely and randomly.

[matstersolo]

So my PC only boots sometimes (as an understatement) but when it does it runs perfectly fine.
Most of the time it has no video output and no usb function and hangs, with no indication it's running apart from fans and LEDS, it turns off instantly from this state upon pressing power button.

I have tried probably every troubleshooting option, that i've seen from any similar issues i've found on forums.
One of note is that I did but another PSU already, however, it is the same model of the PSU I had already. It didn't change anything.
I bought it because my PC ran with all the exact same components fine for a long time before this issue started happening, it was a much cheaper, and of course I don't know if PSU is even the problem so didn't want to spend much.
I've seen other's seemingly having the same issue where a better high watt PSU has fixed the issue but a lot that hasn't.
Was buying the same wattage, same model PSU a mistake?

my components are:
i5 14700k
MSI z790-s wifi
Asus TUF 3080 gaming OC
16gb DDR5
1TB nvme drive
PSU: Corsair CX750