Honestly, GPU API looks awesome, but its entry threshold is much higher than 2D render API. IMO the best solution would be to implement SDL render API on top of GPU API and remove hardware rendering from SDL render API (leaving only software rendering).
For example, I am not familiar with 3D rendering, I have never done it because I did not need it and I still do not need it. The only thing I need is rendering 2D textures on 2D textures, with color/alpha modulation. That is why I use 2D render API, because I do not have to spend time learning all this GPU magic and sculpting in backend APIs (like OpenGL API) — I call one/a few functions and that’s it. Unfortunately, 2D render API does not support shaders, and I will need them to apply simple filters on the final texture of the game frame (bloom, distortion, custom color palette etc.).
That is why 2D render was created, so that everyone could use hardware rendering, without having to delve into how the GPU works at all. It would be very good if the same could be done with GPU API.