Digging deeper into financial modeling

Hi guys, I have an issue regarding financial modeling. I have learned it from scratch from the everywhere-recommended Rosenbaum's book [Investment Banking], but I have a feeling that it is a really flat guide when it comes to many different nuances and real-life advanced modeling. For example there's no description of how to spread debt schedule or deprecation schedule, they base their projections for most of the items simply by taking it as a % of sales, the UFCF is simply EBIAT+D&A+CapEX-change in working cap, completely omitting the equity-based compensation (which sometimes happens to be a really significant item) etc. I am convinced that I could come up with more examples of "inaccuracies", but it is not the point. The point is that I notice those omissions simply because I have heared about certain solutions in modeling here and there, but those aren't event mentioned in the book, so probably there is even more that I am not aware of. So, back to the main issue: how shall I proceed further in order to really deeply and truly understand all of the nuances in the modeling and valuation and what possible sources like books (preferably) or online courses would do the job? The main point is that I want to feel that I have a really deep understanding of the matter and maybe in the end in the most of the cases I will be using simplified models like those in the Rosenbaum's book, but I feel really intelectually dishonest with so limited knowledge.

Also, a side question: I am convinced that such simplified models like those presented in the Rosenbaum's book wouldn't be sufficient for investment pitches prepared for a job interview (HF/AM/SS equity research), because they lack the must-have detailed knowledge and projections required in order to be grilled and not killed by the potential employer (of course it depends on the funds strategy, but you get the point).