> This is also a category of app that I believe could be better served by local-first native apps.

I don't think you even need apps for that. I don't need to save everything forever but I do want to save articles to read offline, after transferring them to the phone:

- I transform the page into an epub thanks to browser extensions (for example this one: <https://addons.mozilla.org/en-US/firefox/addon/saveasebook/>) - I save the content in a special "toread" folder that is synced with syncthing - From my phone I can open all files in pretty much any epub app - With a few scripts I can search in them