You are trying to create a universal library and do not have all the architectures armv7 armv7s i386 x86_64 arm64 . The compiler complains when creating with 64-bit architecture.
To fix this, add the following parameters of your architecture to the static library project:

This requires manually adding architectures to something like this:

Create a library with this architecture on both the device and the simulator, create the library using lipo -create -output "myLibrary.a" ./Simulator/myLibrary.a ./Device/myLibrary.a and use it.
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