Thanks, from LaTeX website, they inform of OverLeaf (not FOSS) more like freemium web app? It works nicely though, Papeeria - also same as OverLeaf in terms of FOSS, and CoCalc which I'm very unfamiliar with and it's different from the first two but also not FOSS webapp. I wish there were apps because I don't even know if there are self-hosteable TeX live equivalent so I could use it without relying on an online service