When creating a new scene with the HDR Template, the scene is completely dark compared to the sample scene.
Sample Scene:

New Scene:

even when adding the example assets to the new scene the scene is too dark:

Game View and Scene View look almost the same in this case aswell.
Go to Window>Rendering>Lighting Settings and at the bottom of the window click the "Generate Lighting" button. You can also set the checkbox to keep it updating automatically.
After copying every single lighting setting from the sample scene into the new scene i still saw no changes.
So i tried a couple of things until i found the solution:
I needed to include the post processing volume into the new scene with following settings:

So i guess before dealing with any more hdr lighting stuff i should look into volumes, reflector probes and light probe groups.
Hope i could help you with that future unity game developer who stumbled upon the same issue.
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