You're certainly welcome BenK91,
In regards to your AirPod connectivity concerns with your Mac, have you checked to see if the AirPods are connected to your iPhone at the time? If you're unsure, check to see if that may provide different results for you. In addition, check out the following resource to see if the steps help out:
If your AirPods won't connect
If you see that your AirPods are connected with your iPhone, or automatically connecting with your iPhone while trying to use with your Mac, see if the steps of the next resource may help at all. This will help to determine if the AirPods are setting the connection to your iPhone as priority over your Mac, and may help with how to switch between both devices.
Switch AirPods between iPhone and other devices
Should neither of those resources help, it may be best to Contact Apple Support once more to see if this can be looked into in detail before working towards a replacement.
Have a great day!