adb install upload location/cache In such cases when performing adb install fails, where does the uploaded APK end up and does it get removed automatically?

I'm trying to workout if there is a cache somewhere that I should be removing after successful/failed installs to save space (without uninstalling the actual app)?
Cleanup should be handled by the operating system.

Logically any temp files generated during installation or a failed install will be reclaimed at some point.

If you are checking the app size in settings: from an end-user perspective one reason why your app is bigger than just the APK is due to Ahead-Of-Time Compilation as well as any resources unpacked from the compressed APK file.

See: Discrepancy between sizes of apps listed in Play Store vs. actual installed app size for more details.