Logitech G Hub Not Working on macOS — The Fix
After installing Logitech G Hub for the G502X, nothing worked. Weeks of frustration until a Reddit thread had the answer.

Go to Settings → Privacy & Security → Input Monitoring and make sure Logitech G Hub Agent is enabled.
Then go to Accessibility in the same section and make sure both G Hub and G Hub Agent are on.
That’s it. Mouse and keyboard work and I can change the DPI settings. No idea why Logitech doesn’t auto-enable these permissions on install.
