Engineering samples of the AMD Ryzen 3 5300G and the Ryzen 7 5700G have been listed on eBay even though AMD hasn't hinted about the arrival of Cezanne desktop APUs yet. There are some shortcomings with these samples, but early benchmarks show decent leads over their corresponding Renoir parts and also the Intel Core i7-10700K.
https://www.notebookcheck.net/AMD-Cezanne-Ryzen-3-5300G-ES-listed-on-eBay-with-decent-performance-gains-over-Renoir-Ryzen-7-5700G-ES-offers-a-10-lead-in-multi-core-over-the-Core-i7-10700K.527454.0.html