Second hand PS4 Pro White

I just brought a PS4 Pro (white) and during gameplay only they seems to be a sound from the back right of the console towards the PSU plug.
If I pause the game and go to a solid menu the sound stops and resumes as soon as i go back to 3D gameplay.
Fan is fine and doesn’t make any noises and the harddrive doesn’t sound like it’s skipping or anything.
PlayStation hasn’t cutout or anything and played for good few hours.
Is this potentially a faulty PSU causing the clicking under high load?

I uploaded a video to YouTube but can’t link it .
At around 8 seconds I enter the menu and you can hear the fan spinning normal without the noise.
First part of clip is during gameplay.

I just brought it but was described as “mint condition” which in England should mean very good condition if not better.
Mint being very good condition (English slang).
Seller says they wasn’t aware and console only had light usage.
I haven’t opened it but it looks really good outside and all screws seem fine with no sign of wear and sticker seems good too.

I am in contact with the seller? Any thoughts or advice?
Would it need a new PSU?
Risk of leaving it?
Cost to replace psu?
I’ve watched a few videos of tronics and think I could replace one.

Thanks in advance!

That noise is called coil whine, and its 100% normal. I don’t believe there is a fix for it as all ps4s have it to an extent.