thanks so much Anna! I think you've sent me where I'm trying to go! I responded in thread but I believe the gist for prefect2 is this from the prefect-dbt collection:

dbt_cli_profile = DbtCliProfile(
                name="jaffle_shop",
                target="dev",
                target_configs=target_configs,
            )
            result = trigger_dbt_cli_command(
                "dbt debug",
                overwrite_profiles=True,
                dbt_cli_profile=dbt_cli_profile
            )

It does not appear that there is a Prefect-native way to mount or pre-load a secret as a file at flow execution time but that's ok because I can get the values from a secret block and then use them in my flow this way rather than trying to worry about files at all