The dream is to have interop between services, but I control the data and can easily make my own views onto it / tools to manage it. I think this is what the MIT solid project is all about, but I'm a bit lost with the RDF and pods stuff.
I often begin tracking something in a text file, then notion or a spreadsheet, but eventually run into issues with the flow and UX, where custom made apps win out, e.g. Todoist has a better task management UX than notion, my habit tracker sends me timely reminders and has a better UX again, and all the other services which are basically CRUD apps with some extra UI/integrations (bookmarking, Goodreads)
I’m currently trying to make Obsidian my storage layer for all these things, since notion is completely closed source & non extensible. The current set of tools I'm working on are - A sync engine to pull 3rd party api data into my obsidian vault - A SQLite vtable/Postgres fdw to expose it as sql so other apps can interop - A notion/obsidian "quick add" app for on the go, like the "intake" part of the OP
If anyone else has a similar itch to scratch, or experience in the area I'd love to hear more (email in profile)