most if not all ram will run at their default speed by default. their full speed has to be enabled via bios. read the description of the different xmp or expo to see exactly how they are set.
also, your cpu arent really the issue with ram speeds. the motherboard is usually the limiting factor. even the 14700K and 14900K supports “only” 5600MT/s. But you can of course usually run higher frequency as long as your MB supports it. Im running mine 64gb at 6000MT/s on a 14700K and Z690P - which is that motherboards maximum supported memory speed. Newer high end boards will support even higher (like you will find many running on this forum).
the cpu contains the memory controller so basically it just handles how fast it can transfer between the ram and cpu. usually if you have higher frequency ram than cpu it just means it will run at gear 2 or whatever.
and yes, not having a QVL list is not fun. Sometimes you can look up the RAM manufactorers QVL/compatibility as they usually also run their own tests on all kinds of systems. In other words, if you cant find a MB memory QVL list, look up the ram manufactorers compatility lists. Kingston, Crucial, Corsair, TeamGroup, Gskill and so on.