merging many jsonb objects using aggregate functions in PostgreSQL?

Is there a standard function in PostgreSQL (as of 12.x) to concatenate or merge many jsonb objects in a database column into a single jsonb object? I know there is a the || operator since PostgreSQL 9.5 to merge **two** jsonb objects. But I need to merge many jsonb objects from a column. The linked documentation does not seem to have one unless I am missing something.