I really like keeping simple markdown files in organized folders, synced with syncthing to all my devices. You only have to set it up once, then you’re all good. Markdown is pretty versatile and fast… people even write books in markdown nowadays.

Markor for android is a good markdown editor, and Typora works for desktop (although typora isn’t open source unfortunately, and its a bloated javascript app, but it does work well).

For bookmarks / favorites, it really makes sense to keep them stored in a markdown file too, that way you can easily search for them and organize them under headings, and you’ll never lose them with any browser changes you do. Its annoying to have to load up a text editor, but at least you’ll always have those.

For habits, loop habit tracker for android is a good way to gradually build daily / weekly habits. Its based on that seinfeld “don’t break the chain” method.

For tasks / todos, the tasks.org app.

Everything I suggested above is open source, offline-capable, and secure. Using things like evernote, google, or dropbox means they’re aggregating that data.