I'm currently writing a report in using Overleaf. As I'm getting the premium version for free through my Uni, I've had no problems so far. Now I'm working in a place with unstable internet and using Overleaf has become very annoying.

Are there some good FOSS alternatives out there, preferably where I can just upload my Project.zip and continue working offline? I have no need to collaborate with anyone or anything like that.

Currently I'm looking at LyX, but I'd be happy to hear about your experiences with that or other programs.