So now standard C++17 or modern Fortran is like writing Assembly by hand?
yes absolutely, way too granular and low level
It's a strange intersection of needs where one wants or needs something like CUDA, but doesn't care to ensure their computation is actually running optimally. If you don't want to be bothered with control and granularity, why are you trying to write high performance CUDA code in the first place?
Would you mind elaborating as to what your hobby project was?
Yes one can make use of the Assembly like low level APIs, which unlike OpenCL, are opt-in, not forced upon everyone.
Clever devs use the high level C++ and Fortran NVidia libraries.