Take a look through and undergrad CS curriculum. A lot of what you're missing would be breadth stuff - math, basic physics, introductory logic, operating system theory, computer architecture, digital systems, algorithms and data structures, compiler theory, finite automata, ...

Personally I'm a big advocate for learning all of this stuff, even if you don't ever need it for your job. It still changes how you think about problems and makes you more well rounded (though formal education is not the only way to be more well rounded).

If you have an undergrad degree or past experience in a different area, you may not be "missing" anything from the perspective of being well rounded.