Nextcloud

Nextcloud is the most complete self-hosted alternative to the Google and Microsoft ecosystems. At its core it syncs files across all your devices like Dropbox, but through its app store it expands into calendars and contacts (synced to your phone over CalDAV/CardDAV), notes and tasks, collaborative office documents, photo galleries, and much more — all under your control.

For anything beyond testing, run it with a proper database (MariaDB or PostgreSQL) and a Redis cache rather than the bundled SQLite; this makes a huge difference to performance and reliability once you have real data and multiple users. Deploy it behind a reverse proxy for automatic HTTPS, and enable two-factor authentication on every account since it holds your most personal files.

Nextcloud rewards a little tuning — configuring caching, cron for background jobs, and sensible upload limits — but the payoff is a private cloud your whole family can use. Pair it with a dedicated photo app like Immich if you want a superior mobile photo-backup experience, and make sure your Nextcloud data and database are part of a tested 3-2-1 backup routine.