Im having a similar error, on 5.4.4 just trying to package for Android ASTC.
UATHelper: Packaging (Android (ASTC)): Fixing minSdkVersion; NDK level is 33 which is above minSdkVersion 26.
UATHelper: Packaging (Android (ASTC)): Fixing targetSdkVersion; minSdkVersion is 33 which is above targetSdkVersion 30.
UATHelper: Packaging (Android (ASTC)): Fixing minSdkVersion; NDK level is 33 which is above minSdkVersion 26.
UATHelper: Packaging (Android (ASTC)): Fixing targetSdkVersion; minSdkVersion is 33 which is above targetSdkVersion 30.
...
UATHelper: Packaging (Android (ASTC)): Z:\app\src\main\java\com\epicgames\unreal\GameActivity.java:731: error: cannot find symbol
UATHelper: Packaging (Android (ASTC)): > Task :app:compileDebugJavaWithJavac
UATHelper: Packaging (Android (ASTC)): activityContext.runOnUiThread(new Runnable()
UATHelper: Packaging (Android (ASTC)): ^
UATHelper: Packaging (Android (ASTC)): symbol: method runOnUiThread(<anonymous Runnable>)
UATHelper: Packaging (Android (ASTC)): location: variable activityContext of type ContextWrapper
UATHelper: Packaging (Android (ASTC)): Note: Some input files use or override a deprecated API.
UATHelper: Packaging (Android (ASTC)): Note: Recompile with -Xlint:deprecation for details.
UATHelper: Packaging (Android (ASTC)): 1 error
UATHelper: Packaging (Android (ASTC)): > Task :app:compileDebugJavaWithJavac FAILED
UATHelper: Packaging (Android (ASTC)): FAILURE: Build failed with an exception.
UATHelper: Packaging (Android (ASTC)): * What went wrong:
UATHelper: Packaging (Android (ASTC)): Execution failed for task ':app:compileDebugJavaWithJavac'.
UATHelper: Packaging (Android (ASTC)): > Compilation failed; see the compiler error output for details.
UATHelper: Packaging (Android (ASTC)): * Try:
UATHelper: Packaging (Android (ASTC)): > Run with --stacktrace option to get the stack trace.
UATHelper: Packaging (Android (ASTC)): 54 actionable tasks: 54 executed
UATHelper: Packaging (Android (ASTC)): > Run with --info or --debug option to get more log output.
UATHelper: Packaging (Android (ASTC)): > Run with --scan to get full insights.
UATHelper: Packaging (Android (ASTC)): * Get more help at https://help.gradle.org
UATHelper: Packaging (Android (ASTC)): BUILD FAILED in 29s