dx11 isn't bad but it has a looot of cruft around it, writing a good constant buffer manager is witchcraft (remember, there's no "loose uniforms" injected into the command stream, it's all constant buffer updates, drivers do all sorts of writecombining magic to mitigate it, but the naive map / unmap cycle without any driver optimisations would absolutely tank....

Look at a GDC talk (https://d29g4g2dyqv443.cloudfront.net/sites/default/files/ak...), efficient dx11 is also "reinvent a diy memory allocator" level except that you don't have much control.

btw you can run dx11 on other platforms because dxvk exists, but while d3d9vk is a solid idea (high-level API, lowering to vulkan often makes it much faster than the crummy MS d3d9 runtime + DDI combo), d3d11vk is just often a wash or even a regression. I've had to debug dxvk-only perf problems a bit too many times...

anyway, point is, it's not really an easy-to-use or intuitive API