You can bypass the compositor and have a single process and display and get effective hard real-time out of it with a dedicated machine like we do for our IGs.
Even for consumers, they can have a second GPU too. Many also do with an iGPU dGPU, although I’ve found that to be problematic to work with for general purpose users.
In any case, the hardware is fine, it’s just the specific typical multitasking use cases managed by existing OSes and drivers that are the problem.
I still believe GPUs offer better hard real-time guarantee potential than CPUs do on any of these OSes, especially when you’re writing to disk. NVMe drives are notoriously bad with their hardware IRQs randomly affecting any core, not just the one used to write to them. I’ve seen 3ms spikes from these. They cannot interrupt the GPU though.