I’ve been using mega.nz and Google Drive. I’ve tried a few other solutions, but didn’t stick with them. Then I tried Proton Drive, and it works fine. But now I mostly use pCloud, because I got a good deal, for a lifetime 2TB, for one payment. This I use now…
I use yWriter, Scrivener (not FOSS, but worth the little money it costs) and LibreOffice. I feel well prepared for any writing.