Dropping all tables in a database

[H]

I am running PostgreSQL  13.11 and tried to drop all tables in a database 
without dropping the database or schema. After logging in as the correct user, 
the following SQL statement does not work:

SELECT 'DROP TABLE IF EXISTS "' || tablename || '" CASCADE;' FROM pg_tables 
WHERE schemaname = 'public' AND tableowner = 'xxx';

The above statement does not drop any tables, nor are there any error messages.

SELECT * FROM pg_tables;

The above shows all tables are still present in the database.

Dropping individual tables works fine but since I need to drop all tables in 
the database in a develop environment, this is not workable.

I had to resort to the following:

-- turn off headers:
\t
SELECT 'DROP TABLE IF EXISTS "' || tablename || '" CASCADE;' FROM pg_tables 
WHERE schemaname = 'public' AND tableowner = 'livraddarpaket';
\g out.tmp
\i out.tmp

The SQL statements above run fine.

Is there some setting I have to change in the database to have the first SQL 
statement to work or have I run into a possible bug?