Bluetooth mouse interfeering with airpods

When I connect my AirPods Pro to a 2013 iMac 21", the mouse experiences lag at regular intervals, usually a few seconds apart. Disconnected AirPods and removed them in the Bluetooth Preferences. Restarted the iMac. Then, follow theses steps.

In Bluetooth settings:

• Make sure you disconnected and removed the AirPods from the bluetooth preferences. And restarted your Mac.
• disconnect and remove the bluetooth keyboard.
• Using the manual bluetooth button on the AirPods case, connect the Airpods
• Reconnect the bluetooth keyboard

This must change some priorities in the bluetooth software settings and now the mouse is no longer exhibiting the lag...