I think it is so. As far as I know, there are no converters that can do that. A search with an LLM made me find https://arxiv.org/pdf/2605.16562, a paper describing the ArXiv conversion tool from LaTeX to HTML; here is a sentence from the abstract:

"corpus-scale conversion work aimed at 90% error-free HTML (currently 75%)"

although there may be issues that I do not understand or did not see (I looked at the paper very quickly) that make it more difficult for the authors than for the simplest possible translation.