What makes multi-tenancy easier in Postgres than in any other DB?
The simple explanation is that you set a postgres environment variable prior to each query. The Postgres row level security system looks at this variable and returns nothing if the ID in the variable does not match an ID in the table.
So I wrote a function in Django which intercepts every database query and prefixes each query with a postgres environment variable set command.
That's pretty much it.
https://www.postgresql.org/docs/current/ddl-rowsecurity.html
But the power of PG is that it doesn't stop there, if you combine this with a plugin like temporal_tables and you can segment by user and time:
https://github.com/arkhipov/temporal_tables
All of this mostly unknown to the thing that's accessing the DB. If that's not enough for you, why not add some auditing with pgaudit:
https://www.pgaudit.org/#section_three
All this value is just out there. There's even more if you can stomach browsing "ugly" sites like PGXN. Most of it works out of the box, though you may need to tinker for performance and some edge cases but it's there.
I think it might not actually be hyperbole to say that Postgres is the greatest RDBMS database that has ever existed.