JDK install

I am having troubles installing some Android tools.

I have done so many things - advice from so many sites :(

So there might be some garbage installed somewhere it shouldn't be.

Now, everything is going ok. It took 6 times to install some parts from the Hub.

But I think that was due to a bad internet connection - damn!

Now, I am having troubles installing the JDK.

In the editor:

In the Preferences - External Tools

1.  JDK Installed with Unity (recommended) [checked]
        "C:/Program Files/Unity/Hub/Editor/2019.3.9f1/Editor/Data/PlaybackEngines/AndroidPlayer\OpenJDK"
        this folder does not exist.
        Error = "You are missing the recommended JDK. Install the recommended version using Unity Hub"
            Unfortunately in Unity Hub - the OpenJDK checkbox is already greyed out.
                I can't seem to uncheck it. So I can't install again :(
   
   

2.  JDK Installed with Unity (recommended) [unchecked]
        "C:/Program Files/Java/jdk1.8.0_251"
        this install exists
        Error = "You are not using the recommended JDK, versions other than 1.8.0 are not officially supported"
   

Can anyone please help? Cheers :)