However much solar or wind energy we use, the Sun will last exactly as long. This is not a matter of scale. Even if we were to build a photovoltaic Dyson sphere around the Sun, it would have the same lifespan.

That is not the case for geothermal. It could in theory be cooled down if exploited at a massive scale.

Saying geothermal is not renewable is not an indictment nor a criticism. Geothermal is great and we should use it more. It's just technically not renewable, but that doesn't matter.