Hey
@Carlos thanks for tagging me in on this 1, nothing gets me more excited than an opportunity to support the PC Master Race... lol...
- How much better is the gaming experience on an Xbox Series X versus a top end gaming computer?
PC is not always better than Console, and XBox is not always better than PS5, but the answer to your question goes far beyond that and should start with you rather than the hardware.
So, about you -
Where will you play?
If you intend to play in your living room on your 75" 4k TV, sitting on your couch, with a giant can of Monster/Red Bull/Duff Beer by your side, then a Console is the answer.
If you have the space to set up a desk where you can have your PC, monitor, keyboard, mouse, speakers, gaming headset, and controller then a PC would be a good option.
If you want something in the middle that's not quite desktop PC specs, but 'better' than a console then a gaming laptop might be another option worth considering, however these tend to have cut down versions of both processors and graphics cards, so an RTX4080 on desktop is a much better graphics card than an RTX4080 on a laptop.
- Intel vs AMD CPU
I have an AMD CPU, so of course I am going to recommend AMD, except I am not, instead I am going to talk about the current range of PC CPUs, Intel has the i3, i5, i7, and i9. AMD has a range of CPUs called Ryzen 3, Ryzen 5, Ryzen 7, and Ryzen 9. AMD have used the numbering scheme that people will recognize from the Intel numbering and as a general rule of thumb each like number should indicate where each processor sits in the hierarchy of performance, the higher the number of stronger the performance. Then we have generations, Intel are on their 13th generation, which is a better performer than the 12, which beat the 11th etc... AMD are on their 4th generation of Ryzen CPUs.
If you're looking at a gaming PC with a $4000 budget then once you have set aside funds for monitor, keyboard, mouse, speakers, headsets and assorted accessories, then that leaves you a big chunk of cash with which to get your PC.
CPUs have a tier that's good for gaming on titles like DOTA and Counter Strike, i3 and Ryzen 3, a tier that's better for AAA titles like CoD/Warzone would be the i5 or Ryzen 5, and if you want the best performance then you would be looking at i7 or Ryzen 7. In my opinion the i9 and Ryzen 9 are better for running creativity software and can perform worse in games than the 7 tier below.
- AMD vs nVidia
Buy as high up from the range as you can afford, but also try and match the resolution you are playing at, people mostly plays at 1080x1920, 1440x2560 or 2160x3840 with each step up in resolution being more demanding on the graphics card, so both AMD and nVidia make GPUs to cover each resolution with a performance tier that's suitable. Pick the resolution and find a GPU to match your requirements.
Due to work and life, I have not been paying as much attention to what's been going on this department, mostly because both AMD and nVidia have not wowed the press as much as they had with previous generation GPUs.
Oh, Intel make GPUs too, but you will need to do your own research on these.
As for buying a PC, I wouldn't know, I have never bought a PC, I build my own, PCPartPicker is a great website to find out about what you should put into your planned PC.
HTH good luck.