I would say Mastodon gives you MORE protection from losing data, not less.
You can set up your own server for approx US$10 a month without technical knowledge or equipment, and then you will be the one who decides when it shuts down.
This option simply doesn't exist on centralised services like Twitter, Google, Facebook etc. They are making you entirely dependent on them, and at their mercy.
On Mastodon and the Fediverse, you can take control for yourself.