Garageband file transfer issue between iPhone 7 SE and iMac on OS Catalina

hi, can anyone help me with Garage compatibility. I have an iMac 19.5 with OS Catalina. My iPhone 7 SE has iOS 18.1.1 

I can not get the iPhone Garageband to send files to the iMac. The Garageband on the iMac will not set my AirPods pro 2 to use as input and output. Do I need to upgrade to OS Sequoia to make this work.

Thanks, David.

[Re-Titled by Moderator]