If you look at the details you can clearly see SDL3_GPU is wildly different from this proposal, such as:

- It's not exposing raw GPU addresses, SDL3_GPU has buffer objects instead. Also you're much more limited with how you use buffers in SDL3 (ex. no coherent buffers, you're forced to use a transfer buffer if you want to do a CPU -> GPU upload)

- in SDL3_GPU synchronization is done automatically, without the user specifying barriers (helped by a technique called cycling: https://moonside.games/posts/sdl-gpu-concepts-cycling/),

- More modern features such as mesh shading are not exposed in SDL3_GPU, and keeps the traditional rendering pipeline as the main way to draw stuff. Also, bindless is a first class citizen in Aaltonen's proposal (and the main reason for the simplification of the API), while SDL3_GPU doesn't support it at all and instead opts for a traditional descriptor binding system.