I'm aware of this (I've been doing since RISC-V before it was public), but it seems unlikely to me, knowing how these companies operate, that Apple would use RI

I'm aware of this (I've been doing since RISC-V before it was public), but it seems unlikely to me, knowing how these companies operate, that Apple would use RISC-V for anything when they already have extensive HW and SW Arm64 IP, expertise, and infrastructure. NVIDIA's use of RISC-V is for the internal power sequencing cores and similar tasks. This is not going into the shaders, nor is Arm64. Their future use of RISC-V for stuff like this will probably continue, but it seems unlikely that they will ever release anything with a user-visible ISA based on RISC-V.