I have the same issue, but it's not a unity project, on some of my Pods I'm getting the same error. If I change the #import from "something.h" to <something.h> it then says framework in <> not found use quotes instead! Can't get it to import them successfully.

Here I am late to the party as usual I've just asked a related question before stumbling upon this thread : https://discussions.apple.com/thread/255363612 I too am looking to use the iPhone 15 Pro's USB C port to talk to devices over serial, for what is an experiment I don't want to spend almost £100 on a Redpark cable. I was hoping to get a cheap USB C to UART/FTDI adapter and plug it in, it's looking like this is less and less likely as a possibility. I know an IP to Serial bridge is an option but I would prefer the flexibility of a direct cable which doesn't need external power and additional dependencies. I did see that Terminus now supports USB Serial using the Redpark cable, and I'm wondering if that is via a generic Apple framework or using the Redpark SDK.