Don't trust proprietary software. Stuff like this will always be a possibility. Syncthing + your text editor of choice (vim in termux on android is actually pr

Don't trust proprietary software. Stuff like this will always be a possibility. Syncthing + your text editor of choice (vim in termux on android is actually pretty good, imo) is a reliable bet. Emacs with org-mode could be used in a similar way. I'm sure there are other combinations as well.