Gemini is actually "Gen 9.5". It has Gen 10 display block, that's why we have a working HDR on those SoCs.
Btw, their next generation low power SoC (Tremont/Jasper Lake/Elkhart Lake) is inferior as far as video playback is concerned. It does not support high quality deinterlacing (MADI, MCDI) and it can only do BOB DI.
Tiger Lake SoC looks awesome (Gen12 GPU, can do AV1 in hardware) but it's expensive.