I've heard that MSI and other motherboard makers will release updates for their current motherboards to make them PCIe 4 compatible with the Rocket Lake chipsets next year, but I can't find a great deal of info on the old Internets... Is this something that is in the works? I'm looking a doing a 3080 build, but wondering if I should wait for the Ryzen 5900x/get a 5800x, as the MBs for those are already PCIe 4 compatible, or get an i9 10900k and update the MB bios next year (if that is in fact the case)? The SSD I bought is PCIe 4 compatible, so would want to get that benefit, but if Intel boards can be easily updated through BIOS etc., then it'll be easier to go that route maybe than waiting for the 5900x to come back in stock... Any insight on this would be greatly appreciated!

In order for PCIe 4 to work you'll need to buy a next gen ("Rocket Lake") Intel CPU and your current mobo will need to have the Z490 chipset. You can wait until those new chips ship and see if SSD benchmarks are matching AMD's PCIe 4 implementation, but if it were me I'd probably just switch to AMD.

That's what I did - got/antsy and ordered a 5900x and MB to suit. Cheers!