There are multiple PAC3220 models. Ensure you are downloading the GSD for your exact firmware version (e.g., PAC3220-PROFINET, PAC3220-ETH). A mismatch will cause "Module mismatch" errors.
In many versions of the TIA Portal Hardware Catalog , the PAC3220 can be found directly under Other field devices > PROFINET IO > Sensors > SIEMENS AG > SENTRON > PMD_V3.0 . Step-by-Step Installation in TIA Portal pac3220 gsd file download