Just to clarify:
Budget: £3000-£3500
Uses: Only gaming
Monitor: Budget of £1000 and your son wants a 4K display?
Is your son buying this himself? i.e it's not a Christmas present?
The reason I ask is that we have new GPU's being released in January and, given your excellent budget, I would...
Definitely, and I can't stress this enough, do not buy an Intel CPU, especially the 14900KS.
https://www.pcspecialist.co.uk/forums/threads/intel-13th-and-14th-gen-confirmed-defective.96599/
We all completely agree, but that frustration should be taken out on Intel, not PC Specialist. They have to sell Intel products, and until Intel recall those products, they'll continue to do so. Many other companies are in the same boat.
I'm not sure I see the link between not registering the PC and Christmas. It's just a phone call to PSC to activate your warranty and give you access to downloads etc. (not that you need them). Your son will never know.
I think you need to adjust your expectations a bit. You’re just not going to get anything worthwhile for just gaming, let alone content creation as well, for the budget you have set. You’re looking at around £1600-£1700 at the moment just for an entry level custom build.
The above build was...
Sounds like fairly standard aftercare. I'm not sure what the alternative was? Sending the laptop back to PCS, they fix it and then send it back to you? That's a lot of time and effort. You deleted the drivers, you perform the fix. I don't see much wrong with the situation.
I wouldn't say that any of it was suitable.
Cheap, unbranded, prone to failure RAM, SSD, Cooler. Low end PSU with zero room for upgrades, Four generation old Intel CPU.
Like I say, you can't just pick the cheapest components possible and throw them into a build.
That's not how RAM works. You can't just add your old RAM to the existing one - it causes instability. They have to be EXACTLY the same. Adding DDR4 to DDR5 just won't work.
The build you've created is completely unsuitable. You've just picked the cheapest components on the configurator and...