What do you mean by installed PostgreSQL 15.3 ODBC driver 8.0 ? Is it that you downloaded the Lite Edition (Single-Tier) ODBC Driver Installer Archive for PostgreSQL 7.x, 8.x, 9.x, 10.x, 11.x and 12.x on macOS 11.x (Universal) and Higher and are trying connecting to a PostgreSQL 15.3 database instance ?
What authentication scheme is your PostgreSQL 15.3 database instance setup to use, which should be set in the pg_hba.conf file ?
With regards to your connection to PostgreSQL 12.x version that is not returning data in Excel:
- What is the Excel version being used ?
- What macOS hardware are you running on M1 silicon or Intel ?
- Can you query the database with the OpenLink sample iODBC Demo application
- If running on an M1 machine please refer to this OpenLink ODBC Driver and iODBC usage on Apple Silicon M1 machines which details some of the possible issues that can be encountered running universal binaries with applications like Excel which may not be universal etc