I just want a PC which will play pretty much any game I want at the highest settings for the next 5 years or so
Well, that's mission impossible there without upgrading at least one part.
Now is pretty much historically bad time to buy expensive graphics card.
Nvidia turns general bang per buck to banged to butt when going to higher models.
And despite of all marketing hype RTX cards have performance crash of 30-50% from use of raytracing.
So no matter how insanely overpriced card you buy, it's likely to look at best "meh" in year for its price.
Hence would recommend now getting good bang per buck GPU for that lowly resolution and upgrading to higher card when prices of next-gen GPU cards have stabilized.
And we have cards actually capable to raytracing...
Also while Intel's advances are only in increasing number of security vulnerabilities, AMD has been going fast forward in CPUs.
So pretty much best bang for the buck path would 8 core/16 thread Ryzen 3700X now and upgrade to 12 core Ryzen (4900?) Zen3 in 2021 when prices of those decreases, like last year's Zen+ Ryzen 2xxx have done.
In year next-gen consoles will bring basically underclocked 3700X as
mainstream.
So for that five year time 12 core is needed to stay in high end, where you don't have to worry about background programs like web browsers starting to affect gaming.
Memory is really third thing.
2x8GB is now enough, with only few games capable to benefiting from more.
But if you keep multitab web browser open in background that amount will start dropping fast:
While I used to do multi-tab web browsing with 16MB RAM PC, now memory consumption of multitabbed browser climbs fast to multiple GBs...
Also next-gen consoles likely come with more memory than 16GB guaranteeing increase in memory demands.
Some rumours give PS5 20GB for games (+separate 4GB for OS) which certainly isn't any overkill considering life span of consoles.
So if you want enough memory to last well that five years 2x16GB would be that, with 2x8GB needing very likely upgrade in two years.
