Reproduction steps:
1. Open project in "nativePluginOSX2.zip"
2. Build for Standalone (make sure "Create Xcode Project" is selected in Build Settings)
3. Deploy the project
4. Function testMethod(); will be called from a Plugin and the result displayed
5. Inspect the Text field

Expected result: Text field contains "3" (returned from testMethod(); PluginImport.cs line 17)
Actual result: Text field contains "System.DllNotFound exception..." which is thrown at testMethod();

Reproducible with: 2019.3.14f1, 2020.1.0b8, 2020.2.0a12
Could not test with 2018.4 because Xcode builds for Mac are not supported

Tested with macOS 10.15.3 Catalina

Note: building fails in earlier versions in some streams because of "Command /usr/bin/codesign failed with exit code 1" error in Xcode