Thanks for your quick reply @OOPer. My mistake- I left out the import of UIKit in the Swift code which caused your error in the demo. Also I'm X-Code 12.3, not sure where I saw 12.5, sorry about that.
I'm still not sure what's causing this issue but it appears to be related to react-native, as I'm seeing the error on a newly created RN project with the above Swift file added.
I created a ticket on the RN issue tracker, so hopefully it will be addressed there. However, I am curious as to how pods could cause this issue. If I set the iOS deployment target to 13.0 shouldn't that force the iOS-13.0 functionality in the Accelerate framework to be built?
Thanks for your help.