AMD GPUs have worked on RISC-V for a couple years at this point. I have a Milk-V Titan that's paired with an AMD GPU running well: https://milkv.io/titan

Maybe a Zen microarchitecture with a RISC-V/RVA front-end?

While thinking about it, if NVIDIA or SAMSUNG go performant RISC-V CPU micro-architecture, will "probably" change the world.