@zenfin@mementomori.social @slava@mathstodon.xyz PDF and Unicode support are pretty good with lualatex, but what you can't fix is, that latex is a language based on textual replacement and not on a parsed AST and as such never will have good error messages, since the TeX engine lacks the necessary context. That's the unfixable issue with everything TeX related. Also: the reproducibility is a strong claim, that only holds true, if you find the correct engine and compatible packages. Chances are, a maths paper from 1990 will not build with lualatex without modifications and even then certainly not match pixel perfect.