There is now a big rumor going around that AMD will postpone the release of the next processors. Intel's 13th generation, which should also be available on September 29, is not the reason.

Ryzen 7000 CPU's delayed; Image: Hardwaretimes
According to the Hardware Times, the Ryzen 7000 CPUs will be delayed to market because motherboard partners still need to fix bugs, otherwise it could lead to serious problems for users, according to the Hardware Times
AMD is currently rebuilding their AM5 platform from scratch, so this will require a lot of testing and a lot of patience, especially considering that the motherboards will support DDR4 and DDR5 ram.
Minor bugs will still be present when the Ryzen 7000 CPUs are released, though. We all hope that these will be fixed as soon as possible.