Everything important is constantly synced between my laptop, PC, and server using Syncthing. Then every 12 hours a snapshot is taken of those synced folders, which is stored on another server in a different location using Kopia, which keeps latest 3 days, latest 3 weeks, and latest 3 months snapshots available.
That means at any given time there’s a copy of my data on 4 devices resilient to one of those devices disappearing, and 2 logical devices in terms of accidental deletion/corruption (laptop, PC, and server maintain identical copies live so aren’t protection against that, but Kopia is since it maintains historical snapshots).