What's new and My Work sit on top of TeamHub and read across every team you belong to. One stream for everything that happened. One overview for every task waiting on you. Both are places you act not just places you read.
Being useful in more than one team means checking all of them, messages, open decisions, board cards, file approvals, the meeting somebody added you to yesterday. The cost isn't any single check, it's the round trip: every team, every tab, every day, to find the three things that actually needed you. Miss one and it comes back as a chase-up a week later.
What's new gathers every teams communication into one stream. My Work gathers every task from those teams that are waiting on from you into one overview, ordered the way you want. Both read across all your teams at once, and in both you can reply, approve, complete or vote without leaving the page.
Every layer only adds to the one beneath it. Nothing is copied and nothing becomes a new silo. The personal layer reads the teams you're already in, and each action you take there writes straight back down to the connected apps or teams. The source app stays the source of truth.

Download TeamHub from the Nextcloud app store and request a trial license from the TeamHub admin settings license tab. What’s new and My Work appear in the sidebar the moment the licence is active.