I already solved this issue, just putting this here for anyone struggling with the same issue:
When I attempted to upload the Android build of my Ionic app, Google Play Developer Console told me I needed a Target SDK of 31.
I was able to update this by updating my config.xml to have this line
<preference name="android-targetSdkVersion" value="31" />
But then when I would build my app it would fail with the following error without any real indication of what to do next
Task :CordovaLib:compileReleaseJavaWithJavac FAILED
An exception has occurred in the compiler (1.8.0_202). Please file a bug against the Java compiler via the Java bug reporting page (http://bugreport.java.com) after checking the Bug Database (http://bugs.java.com) for duplicates. Include your program and the following diagnostic in your report. Thank you.
java.lang.AssertionError: annotationType(): unrecognized Attribute name MODULE (class com.sun.tools.javac.util.UnsharedNameTable$NameImpl)
FAILURE: Build failed with an exception.
* What went wrong:
Execution failed for task ':CordovaLib:compileReleaseJavaWithJavac'.
> Compilation failed; see the compiler error output for details.
* Try:
Run with --stacktrace option to get the stack trace. Run with --info or --debug option to get more log output. Run with --scan to get full insights.
* Get more help at https://help.gradle.org
Deprecated Gradle features were used in this build, making it incompatible with Gradle 8.0.
You can use '--warning-mode all' to show the individual deprecation warnings and determine if they come from your own scripts or plugins.
See https://docs.gradle.org/7.1.1/userguide/command_line_interface.html#sec:command_line_warnings
BUILD FAILED in 3s
22 actionable tasks: 2 executed, 20 up-to-date
Command failed with exit code 1: /Users/danielread/Documents/GitHub/fitdegree/clients/apps/app/platforms/android/gradlew :app:bundleRelease -b /Users/danielread/Documents/GitHub/fitdegree/clients/apps/app/platforms/android/build.gradle
I was able to fix this by updating the version of Java on my computer.
Previously I was on version 1.8.0, after upgrading my Java to version 11 the build was successful.
https://www.oracle.com/java/technologies/downloads/#java11
I also updated my gradle version but not sure if this was neccessary
brew upgrade gradle