Based on leaked benchmarks I saw from some Brazillian youtuber last night, at 1080p the 5600x is out-preforming the 10900k in most games. I think at the time 3700x was competitive with the 9900k. I think if you're going for an upgrade, getting in on Zen 3 will be very benefitial, especially if you're not already on Zen 2.
For a pure gaming workload the 5600x is going to comfortably be the faster chip.
Hmm, I'm basically building an almost entire new PC. That said, I could get the 3700x cheaper than the 5600x, specially factoring in the import fees. That would increase the 5600x a lot more I think, so I'm gonna check reviews and make a better informed decision. Specially with games that uses more cores and all stuff