Many flagship Foss programs are cross-platform!

You can run Libre Office right now on your you computer! It does everything you want in an office suite _and_ it has a stable file format so your text files will look the same even if you open it on a different computer. (I know file formats are boring, but it really is very nice to have one that works properly.

I wrote my PhD in a Mac version of libre office and it was probably the lowest stress part of writing that paper.

They're on fedi. @libreoffice