AirPods Pro 2 Spatial Audio setup

So but of a complicated one,

I’m about to buy AirPods Pro 2 and want to use the Spatial Audio feature, however I have an iPhone SE 2nd gen. I know this will not work on this phone for the setup. But my mum does have an iPhone 15, so can I set up this feature on her phone then reconnect the AirPods back to my iPhone SE and still have correct and working special audio, or will I need to sign into Apple ID on her phone.

another issue with that, I need to make sure that absolutely no data is transferred between the two devices because there is sensitive data on both phones, is this still possible