New iphone 15 pro max will not show up in itunes on my Macbook ( mid 2010 )

I was using an iphone XR and bought an iphone 15 pro max. I am trying to sync my 15 with my mac. When i used the XR it would show up in itunes so i could sync. My XR is still connected to my mac. When i try to connect my 15 using a usb cable it does immediately start charging however when i go to itunes on my mac the 15 does not show up in the sidebar or at the top of the itunes page. I can not figure out why it won't show up like my XR did. Does the fact that the XR is still connected interfere with my 15 showing up? Is there something in settings I'm not doing? I'm at a loss. Any help would be appreciated as I've been trying to figure it out for 2 weeks. My 15 connects to bluetooth, my photos show up on the mac. I just can't sync or back up anything. Thank you for any suggestions. Victoria