Just some extra info, notice this error here…
UATHelper: Packaging (Android (ASTC)): Build-tool 31.0.0 is missing DX at C:\Users\rober\AppData\Local\Android\Sdk\build-tools\31.0.0\dx.bat
I get this same exact error every time I install it…apparently either Unreal is expecting d8.bat and d8.jar to be named dx.bat and dx.jar or the installation for the build-tools is screwing up the naming convention…
I actually was able to fix this error just by duplicating those files and re-naming them. If you check the Github repository bug reports there is actually a thread that was opened specifically inquiring about this and reporting it as a bug. This wasn’t even reported as a bug for Unreal, it was reported by coders that use this build tool outside of Unreal.