For other topics that aren't strictly programming, eg AI, ML, game theory, cryptography, quantum computing, probabilistic methods, optimization,... it would take a significant amount of dedication to match the amount of understanding that a rigorous course with problem sets can give you in self study.
Also, you're going to have an extremely difficult time getting to work on that stuff without a degree, given that even PhDs often end up on regular business bullshit.
Also, you're going to have an extremely difficult time getting to work on that stuff without a degree, given that even PhDs often end up on regular business bullshit.