I think now I'm going to order the msi tomahawk x870 wifi with some gskill 6000 cas 30. I thought about getting 6400 but I'm coming across info on the web saying it's a crapshoot and 6000 is good enough while almost guaranteed to work.
I can't guarantee that every CPU can make that, but every ASRock X870/X870E and Gigabyte X870E I tested could make 6400 1:1 stable and post at 6600 1:1 on my pretty average 7950X. Also ASUS X670E/B650E and Gigabyte B650E. 9 or 10 mobos in total. Only Biostar couldn't make it. On the other hand, every 6000 CL30 kit that you buy should easily make 6400 CL30/32.