Honestly, since you already have an 8086K, if I were you I'd just wait another year before upgrading. You're not going to see much difference in most games. If you wait you can get onboard with a DDR5 platform.
If you're going to upgrade I definitely wouldn't get an 8 core processor as that will be a negligible improvement--not even worth the hassle of even upgrading, IMO.
I'd look at a 10900F, or a 10850K. The giving up the K for an F results in a pretty cost savings, and although the F can't be overclocked my understanding is you can still run it with MCE. Since there's so little left in these CPUs anyway you're not giving up much by forgoing the K.
I'd probably also look at saving money by going with a solid Z490 board instead of a Z590. A lot of Z490 boards support PCI-E 4.0 for the GPU, but it doesn't matter anyway since 10000 series CPUs don't support it. And either way there's no real upgrade path, so I don't see much to be gained by going with Z590.