The thing is, even NVidia GPUs have PCI-E 4.0 now (with Ampere line-up). And only AMD offers a consumer platform with PCI-E 4.0 support. So if you want to play @ 4K60, then you're going to want something with PCI-E 4.0, IMHO, alongside an Ampere (or Big Navi) card. Intel won't have PCI-E 4.0 on a consumer platform until Rocket Lake, which likely won't be until 2021. Plus, I heard in a HardwareUnboxed video, or maybe it was GamersNexus, that many of those so-called "PCI-E 4.0 Ready" Z490 boards on the market right now, may not, in fact, turn out to be fully PCI-E 4.0 "ready" (*) for Rocket Lake, and that a new generation ("Z590?") chipset will be announced corresponding with Rocket Lake release, which will be fully "PCI-E 4.0 Certified" on Intel platform. But again, you'll have to wait until some time in 2021, most likely, for that to happen.
(*) Remember many years ago, when many consumer PCs were sold with Windows 98se/ME/2000, as "Vista Ready". And yet, they weren't. Yeah, that.