To reproduce:
1. Make sure that Unity is installed in a directory that requires admin rights to edit e.g. C:/ disk
2. Run this command:

"C:*Unity install dir*\Editor\Data\PlaybackEngines\AndroidPlayer\SDK\tools\bin\sdkmanager.bat" --uninstall "platforms;android-30"

3. Delete Java if already installed on the machine
4. Create a new project
5. Switch to Android platform
6. In Project Settings set Target API Level to 30
7. Try to Build and Run to an android device

Expected: the API level is installed or a warning that no Java is install is thrown
Actual: getting an error in the console, API level is not installed, build fails

Reproduced on:
2020.1.12f1