They're merely rebranded Intel Core 13th Gen chips, with a performance difference around 1% at the same clock frequency. Reviewers found their CPUIDs report the same model and even stepping. Some rumors previously claimed possible minor improvements to the on-die memory controller or voltage regulation, but both turned out to be false. The only differences are slightly increased clock frequencies, and also slightly increased L2 and L3 cache sizes in some lower-end SKUs (that were already physically present on the silicon but previously fused off in cheaper models). Thus, think of them as some new SKUs in the 13th Gen product line with slightly higher specs at the same MSRP (but may or may not be cheaper at retail prices).

Apparently the reason is that Intel was experiencing production difficulties on Meteor Lake, so this new generation is skipped for desktops in favor of an exclusive launch for mobile (and HTPC desktops) platforms. Wait until December 14th, 2023 for the real new CPUs.