Zen 4 is rumored to launch in late 2022, so later this year and in early 2022 we will be getting only refreshed Zen 3+ models. According to a new leak, the first products to integrate the 6 nm Zen 3+ tech will not be the desktop models with V-Cache or the Rembrandt chips for laptops, but the Ryzen embedded V3000 launching in late 2021. These processors will feature support for USB4, DDR5-4800 RAM, and will have a maximum 35-54 W TDP with integrated RDNA2 iGPU.
https://www.notebookcheck.net/AMD-rumored-to-launch-Ryzen-embedded-V3000-processors-with-6-nm-Zen-3-cores-and-RDNA2-iGPUs-supporting-DDR5-4800-RAM-and-2x-USB4-connectors-in-late-2021.546945.0.html
These should be almost identical to Rembrandt, just with ECC support and some other features.
We still don't know if Zen 3 on 6nm is worthy of a '+' and will have an IPC gain. Maybe they could add more cache than Cezanne, even if it's not V-Cache amounts.
"the V3000 processors with 12 CU iGPU should also make for very good upgrades in handheld gaming PCs like the the GPD Win series."
Or they'll just use Rembrandt.