Check out git-annex: https://git-annex.branchable.com/

It’s super cool if you know git. It lets you track where your files are without having them all in the same place. You could have a bunch of disconnected hard disks, and git-annex will remember where you put your stuff.

You can also set a minimum number of copies and it will only let you delete stuff from one place when it’s sure there are sufficient copies elsewhere.

I do not recommend using the assistant (edit: nor the webapp) if you’re planning on ever reviewing the repo’s history. It generated a bajillion automatic commits that drown out any handwritten commit messages.