Alas, no luck. Getting “Platform Android is not a valid platform to build. Check that the SDK is installed properly”, though I followed this page to set up Android Studio & SDK to the last letter.
It’s just really confusing. These are my Android SDK Platforms settings showing that API v34 is installed, plus 10.0 (Q) - which is somehow also v29:
SDK build tools are versions 34.0.0, 33.0.1 and 30.0.3:
NDK “side by side” is v25.1…:
Trying to find a solution for the “SDK not installed properly” issue I found this page and Iooked at the Android SDK location (“edit” on the first image above) and this showed:
… I cannot check the first box before Android SDK - maybe because it is installed, but then I would expect it to show a greyed-out checked box?
Anyhow. Back to the Unreal editor, I have these versions listed in Project Settings → Platforms → Android:
that mentions SDK versions 24 and 26 - that last one being the target version. I cannot tell if that’s supposed to go together with any of the versions mentioned in the Android Studio settings, ie. 29, 30, 33 and 34: the Android versioning system sure isn’t the most straightforward ever 
And here are my Android SDK platform paths:
Running platforms → Android → cook content ends hopefully with
UATHelper: Packaging (Android (ASTC)): Installed Sdk validity:
UATHelper: Packaging (Android (ASTC)): Android: (Status=Invalid, Allowed_Sdk=r25b, Current_Sdk=, Allowed_AutoSdk=r25b, Current_AutoSdk=, Flags="Platform_ValidHostPrerequisites")
UATHelper: Packaging (Android (ASTC)): Will install 'Android SDK r25b'
UATHelper: Packaging (Android (ASTC)): ----------------------------------------------
UATHelper: Packaging (Android (ASTC)): Running 'C:\Program Files\Epic Games\UE_5.3\Engine/Extras/Android/SetupAndroid.bat android-33 33.0.1 3.10.2.4988404 25.1.8937393 -noninteractive'
UATHelper: Packaging (Android (ASTC)): ----------------------------------------------
UATHelper: Packaging (Android (ASTC)): Scanning for envvar changes...
UATHelper: Packaging (Android (ASTC)): ... done!
UATHelper: Packaging (Android (ASTC)): ----------------------------------------------
UATHelper: Packaging (Android (ASTC)): Finished with 0
- though it says that it “Will install ‘Android SDK r25b’” (next to those versions it already has?) - how on earth it arrives at the conclusion that it needs to install version r25b while Unreal has min version 24 / target 26 specified, and Android Studio provides a half dozen more recent versions, I don’t know.
But to add the cherry to the pie, the package command finishes with:
UATHelper: Packaging (Android (ASTC)): Platform Android is not a valid platform to build. Check that the SDK is installed properly.
UATHelper: Packaging (Android (ASTC)): Took 0.45s to run dotnet.exe, ExitCode=6
Honestly, I have rarely been so immensely confused. And that’s not even considering what “ASTC” is (and if I need it) and what the difference is between OpenXR and “regular” XR.