I upgraded Xcode from 12.2 to Xcode 12.3 and after upgrading, the build fails on the ArcGis framework with this message:
"Building for iOS Simulator, but the linked and embedded framework 'ArcGIS.framework' was built for iOS + iOS Simulator."
Here's a Stackoverflow thread on the issue (not ArcGIS specific though):
https://stackoverflow.com/questions/63607158/xcode-12-building-for-ios-simulator-but-linking-in-object-file-built-for-ios
Also, you might want to consider distributing XCFramework files to be able to support multiple architectures properly.