mesutt it's because the camera is always meant to look at the floor. If you want to allow offsetting on Y, you can use the allowYoffset feature.
Open FocusOnClick.cs and change
if (follow)
CameraEvents.OnRequestObjectFollow?.Invoke(gameObject, focusOnFollow, false);
else
CameraEvents.OnRequestObjectFocus?.Invoke(gameObject, false);
by
if (follow)
CameraEvents.OnRequestObjectFollow?.Invoke(gameObject, focusOnFollow, true);
else
CameraEvents.OnRequestObjectFocus?.Invoke(gameObject, true);
you can also try the "free camera" component which is not relying on the floor at all.
Hope this helps,
Anthony