That's just wrong, it's worked fine for me on every AMD card i've owned dating back to at least the HD5000 series cards.
Looks like a detection issue to me, it's not detecting your current drivers and displaying 'RX 3750 XT'? in the monitoring graph.
I would DDU the current drivers, uninstall AB whilemaking sure to remove the user profile settings, it should prompt for this while uninstalling, then start with fresh drivers and reinstall AB.