Welcome to the Airtable community!
Airtable probably isn’t the best back end for a social networking app with a huge number of users. Each base in Airtable is limited to 50,000 records.
If you want to use one user license and the REST API to build a front end, that would not be a no-code solution. You could use Stacker or Mini-Extensions or other portal software that provides user level permissions, logins, for a no-code solution. However, you are still going to hit that 50,000 record limit.