I would recommend using the lwarp package for turning large latex documents into HTML. Pretty much all other converters attempt to parse the tex files, which is

I would recommend using the lwarp package for turning large latex documents into HTML. Pretty much all other converters attempt to parse the tex files, which is an almost hopeless task. Lwarp has a different strategy: it redefines all macros to produce HTML (e.g. \textbf{example} writes "<strong>example</strong>" into the output pdf) within latex, thereby producing a PDF containing HTML code. It then uses a pdf2txt extractor to get the finished HTML file. Thus, it uses latex to parse the latex. Lwarp worked for me to produce an HTML version of the TikZ documentation (https://tikz.dev https://tikz.dev), and that's probably one of the more complicated tex documents that exists. (Though granted, this was still a major effort.)