I'm actually curious what you're doing that causes this. Basically all my figures are \begin{figure}[ht] and everything works out fine. Yeah sizing can sometimes be odd but I save it for the end (I use \includegraphics[width=0.x\textwidth] and adjust x. I get it in 2 or 3 attempts). I only invoke graphicx. I use \FloatBarrier frequently but that's trivial. I use jpg, jpeg, png, and pdf images almost exclusively (wish gif worked and wished mp4 would save into the pdf). I do also invoke tikz and pgfplots when I'm making vectorized plots and graphs (I know this is "advanced"), but I'm not writing tikz pictures in most documents. I do all my homework, papers, presentations, etc (PhD student) in LaTex. Been using it for almost a decade now and I've only faced placement problems when I was just starting and didn't know about [ht] (or [h!]).

I'm not sure what you find difficult about margins. You define them in document class. It is literally top, bottom, left, right, or height, width. Or you use the template that a publication is giving you. Are you doing something more complicated? If so, I can't imagine this is common.

Headers and footers? I never use headers. But I use footnotes (\footnote{this is all you need}).

Honestly I'm curious what issues you face. I'd gladly lend a hand (LaTeX is far from trivial) and I'd like to learn from others. But I'm honestly confused at the complaints. There's plenty of things to complain about LaTeX, but these aren't the challenges I face.