If the build doesn't show up on App Store Connect. You may want to check your email (the one you used as your Apple Id when uploading the build). In my case Apple sent me an automatic email telling me that my build had some issues. Xcode didn't complain about anything nor App Store Connect.

Same Here ITMS-91061: Missing privacy manifest - Your app includes “Frameworks/FirebaseCore.framework/FirebaseCore”, which includes FirebaseCore, an SDK that was identified in the documentation as a commonly used third-party SDK. If a new app includes a commonly used third-party SDK, or an app update adds a new commonly used third-party SDK, the SDK must include a privacy manifest file. Please contact the provider of the SDK that includes this file to get an updated SDK version with a privacy manifest. For more details about this policy, including a list of SDKs that are required to include signatures and manifests, visit: https://developer.apple.com/support/third-party-SDK-requirements.