We've been building part of this at https://mana.ai! Our goal is to provide data that's even richer than Chronofile effortlessly using integrations (as you mention) and AI.
We currently support desktop agents (Windows, MacOS), Calendars (Google Calendar, Outlook), health monitors (Apple Health, Google Fit), as well as Chrome, Slack and a few others.
We're big supporters of MyDataGlobal and the OpenHumans movement, and have a few features for export in the product already. Happy to chat if you'd be interested in a way to feed out just the API data we're already managing so you can use it elsewhere, DM me or mail support@mana.ai and I'll see it!
Oura ring however has an open API, I don't own one or use it but worth checking out - https://cloud.ouraring.com/docs/