I also have a love & hate relationship with LaTeX. I think it really boils down to the following:

LaTeX will work excellently for you, so long as your use case was envisioned by the original authors.

I can't say that the original authors of LaTeX didn't envision using it for creating slideshows/presentations, but I can say that making a beamer theme is uniquely complicated. I wish that LaTeX had something as flexible as CSS for styling documents rather than the awkward commands, etc. used now—so much so that I attempted to replace LaTeX with a HTML & CSS -> PDF workflow in the past [0]. It is still an idea I want to revisit someday when I have more time.

[0] https://github.com/jonpalmisc/pmt (no longer actively maintained)