Listing on the QVL simply means it has been tested and validated to run at the rated speed. If something *isn't* on the QVL that doesn't imply anything. It could be that something was tested and failed or it could just mean that Corsair didn't send Asus a kit to test. Or it could be Asus tested and it failed with that particular sample CPU but your CPU's memory controller might be stronger and everything works. The QVL is simply a guideline rather than a hard compatible/incompatible list. Given the current situation with DDR5 I would buy what I could and just make sure to purchase from a retailer that accepts returns if it doesn't work.
It's also worth mentioning that you might get a 5600 kit that won't run at 5600 but you can bump it down to 5200 and it runs stable. So even kits that were tested and didn't make it on the QVL might still work just fine with some tweaking.
One other question regarding this; if i was to buy TWO kits of the Corsair Dominator 5600mhz CL 36 Memory would i be able to populate all four slots and have the work at the rated speed? Having looked at the QVL lists on some other motherboard manufacturers websites, they seem to imply that you cannot use more than two sticks of certain kinds of memory? Forgive me if this is a stupid question, while i have built my own computer a couple of times before some of the technical aspects are still a bit confusing to me.