Every motherboard has max RAM frequency in the specs for 1DPC so 2 slots. Most manufacturers in the current generation declare not much different max RAM speed in specs than it works in real. The only exception seems ASUS in their higher series mobos. For example, they declare 8k for APEX series and motherboards have 8800 OC profile in BIOS. I guess they protect themselves in case of below average IMCs. Even if you get the best overclocking motherboard, then many CPUs have problems with more than 8000 fully stable. My 13700K was barely stable at 8400 and could barely post above it. 14700K that I have now wasn't fully tested but it posts at 8800. Nothing really special, but at least better than the last one.
I'm curious if the Nova overclocks any better as all other ASRock Z790 motherboards could barely pass 7200. ASRock used to be great in RAM OC, but the last two generations are pretty average with worse than usual BIOS support.