Please recommended learning material on how graphics works in Unity

I'm looking to develop a deeper understanding of how Unity's various graphics pipelines work, from a beginner/intermediate perspective. I think I have some misconceptions about how rendering actually works. If anyone can recommend something (paid is OK) where I can answer some of these questions, I would greatly appreciate it:

- I know the basics about batching, draw calls, etc. but would like to learn more about how draw calls actually work.
- When do assets get pushed to GPU memory and how long do they stay there? I have long assumed all meshes, textures, etc. get pushed to the GPU at some point and live there forever. After being introduced to SetPass and GPU context switching, I'm not sure anymore.
- Why does the CPU become a bottleneck when switching materials on the GPU? Can't we simply tell the GPU to render Model A (at position X in GPU memory) with Texture A (at position Y in GPU memory). I don't understand why the CPU has to do any work at all, since the GPU should already have everything it needs.
- What is the actual material difference between URP and HDRP? I've been told things like "HDRP has more stages" and "HDRP looks better" but I have no idea what that means.
- How does animation instancing work? Why (and how) are animations baked into a texture, and why a texture instead of arbitrary data like a compute shader?

If anyone is willing to mentor me on the subject, I'm willing to pay for your time. Please send me a PM.

If you can't recommend a learning resource, maybe you can help me piece together better understanding and I can publish a learning resource for free.

Thanks for your time.

 

Suggest you try learning about shaders as it’s a nice rabbit hole to jump into and learn all about how things work