In you're in it for the money, then forget about HPC and the mathy stuff, unless you've a PhD in the application domain, no one will bother with you, even if you write CUDA at 120 wpm.
The real money is in mastering PTX, nvcc, cuobjdump, Nsight Systems, and Nsight Compute. CUTLASS is good open source code base to explore - start here https://christianjmills.com/series/notes/cuda-mode-notes.htm...
most importantly, stay off HN, get on Discord gpu mode, where real coders are: https://discord.com/invite/gpumode