Both AMD and Intel publish on their site, for each CPU model, the maximum supported memory speed.

If the CPU does not work at that speed, you are entitled to a replacement or a refund.

For instance, AMD Ryzen™ 9 9950X3D is guaranteed to work with DDR5-5600, but with nothing faster. No AMD non-server CPU goes above this limit for DDR5.

Some of the Intel CPUs are guaranteed to work with faster memories, e.g. Core Ultra 9 285K with up to DDR5-6400, and the very recently launched Core Ultra 7 270K PLUS with up to DDR5-7200.