Thanks for that kksnowbear. I think the z490 ASUS boards will only be adding the new CPU support, and that PCIe 4.0 is probably a typo on the bottom of that page
https://www.asus.com/microsite/motherboard/Intel-Z490/Other places just say CPU support but who knows, fingers crossed they have secret 4.0 in there.
A beta BIOS is available for my board (Asus ROG STRIX Z490e) and only mentions CPU support in the text too.
"Version 2004 Beta Version
2021/01/15 8.81 MBytes
ROG STRIX Z490-E GAMING BIOS 2004
-Support 11th Gen Intel® Core™ Processors
- improve ReSizable BAR compatibility for NVIDIA RTX30 series graphics cards"
