In addition to exporting one's contacts from Facebook in order to import them into an alternative, there should be a way to use whatever is provided through Facebook's "Download your data" to populate new accounts in the new alternative.

Perhaps it already exists but I have thought about writing something that takes what is provided by "Download your data" and produces a local SQLite database, a local webpage, local website or some combination thereof that is served from the user's computer instead of Meta servers.

However I do not use Facebook enough to justify the effort, and when I do I never look at the "feed".