If you are still searching for "forticlient 6.4 3 download macos" instead of using version 7.0+, consider these trade-offs.
Once the .dmg file is downloaded, follow these steps: forticlient 6.4 3 download macos
Release notes says only Forticlient MAC 6.4. 3 officially supports Mac OS 11+. Not sure if this version could fix your issue. FortiClient (macOS) Release Notes - AWS If you are still searching for "forticlient 6