If you sign your data it becomes self-authenticating. True, you'll never have 100% certainty that your data won't be removed unless you self-host, but you can replicate your content across multiple more or less trusted hosts, who would all have to deplatform you at once for it to be effective. You can also keep a back up and re-upload it to a new host at any time. This is good enough for most people, and the option of self-hosting is always open to people who feel they have a higher risk of deplatforming.