RYZEN 3700X OR 5600X?

Neither, go with Intel

Only joking, there isn't that much between the 3xxx and the 5xxx at that kind of budget, but at least you'll have 8 cores.. Then again it depends what you do, if there's a rather large saving dropping a couple of cores, 6 core 12 thread isn't exactly bad for gaming though jumping from an 8086K to a 9900K did help me out quite a bit!

Largely what Ani says is right though (i could mock AMD doing chiplets yet years ago everyone hated on Intel for the same thing (Core2 days) and there are issues running things that way..) but with the chiplet approach apparently causing concern, maybe go Monolithic if you get a good deal. AMD doesn't exactly overclock well and if you don't plan on doing so, non-K Intel CPUs can be had cheap too. And generally win on IPC! Don't believe the hype much like all, it depends on the games/applications used so i'll second that: check benchmarks.

And for anyone that thinks i'm biased/fangirlism, i say nope: i go with what works for me. It's usually Intel, but my custom built router is actually running an AMD SoC as it was better than a similar Celeron based (lol) ITX board i had, though i had to sacrifice 8GB of RAM for just 4GB.. In terms of IPC the cheaper, actually cooler running Celeron won.. However i now have native AES etc acceleration and despite some of the vulnerabilities i haven't had to do any Kernel or software mitigation due to the Spectre/Meltdown shitshow that AMD are just as guilty of, but that's another story. Heck, even the Ryzen based machine i built for someone needed a BIOS/UEFI update to fix vulnerabilities. Unless you're running big VMs or other enterprise/corp software, there isn't so much to worry about! Seeing my router say "AMD SoC with integrated Radeon HD8350" or whatever it is makes me chuckle though, not sure why!

As annoying as it is to wait, at least let things settle down.. At one point i could have sold my old 1080 Ti for a ridiculous amount.. as it was a friend kindly paid me £500 for it, but i did just build his rig (he got really lucky - he was sent an i9-9980XE accidentally instead of a 10900X.. he got an 18 core CPU for the price of 10!) and that then went towards the massively overpriced RTX 3090... But it was worth it for me just due to the amount of RAM - otherwise a 3080 would have been a much better choice! And we have the same "SmartMemory" crap now too, which has actually been disabled for like, a decade and a half anyway.. (Resizable BAR.. seeing "Aperture Size" in my BIOS again really takes me back to the good old days! XD)