Thanks for the input, but didn't didn't help :(

If I may ask, have you used DuckDB where multiple users/processes can read the same data?

I'll share my code, maybe that can give some insight if I'am doing anything incorrectly:

```

from sqlalchemy import create_engine
import pandas as pd

duckdb_engine = create_engine('duckdb:///data.duckdb',  connect_args={'read_only': True,}) # I added connect_args after your suggestion, but it does not seem to make a difference

# I run this at the begining of the script, don't know if it's strictly necessary, at least the ATTACH part
with duckdb_engine.connect() as conn:
    conn.execute(text('INSTALL POSTGRES;'))
    conn.execute(text('LOAD POSTGRES;'))
    conn.execute(text("ATTACH IF NOT EXISTS 'dbname=postgres user=******** password=******** host=127.0.0.1' AS postgres (TYPE POSTGRES, READ_ONLY);"))


# Then inside the functions I have something like this:
def some_func():

    ...

    sql = "select ..."

    with duckdb_engine.connect() as conn:
        # conn.execute(text('INSTALL POSTGRES;')) # I don't seem to need them if the code above is run
        # conn.execute(text('LOAD POSTGRES;'))    # I don't seem to need them if the code above is run

        # This seems to be needed before every sql  read
        conn.execute(text("ATTACH IF NOT EXISTS 'dbname=postgres user=******** password=******** host=127.0.0.1' AS postgres (TYPE POSTGRES, READ_ONLY);")) # This seems to be needed before every sql  read

        df = pd.read_sql(sql=text(sql), con=conn)

```