No Nvidia cannot do that. Unified memory only works if both GPU and CPU can access that memory quickly. With dedicated GPUs that doesn’t work because data must travel over a slow bus. Sure you can have unified memory but with major performance problems which defeats the purpose.

If you want high performance GPUs and CPUs with unified memory then you need an SoC. Nvidia is also moving in that direction which is why they wanted to buy Arm.

Separate GPU and CPU has no future in high performance computing.