I know it’s possible to export everything now. But it seems unwise to rely on that being possible indefinitely. A process for regular complete backups seems like something it would be good to make routine well before there seems to be any concrete reason to worry.
For the purposes here, I don’t think relying on yet another commercial service (gitlab, gitea, …) is a good idea. You want a regular backup, using free/open-source tools, to open formats like JSON etc.