From the Jain perspective, we cannot definitively say that Gautama Buddha reached moksha.

In Jainism, moksha is attained only when all karmas are completely destroyed through right faith, right knowledge, and right conduct. Jain scriptures and tradition do not clearly establish Gautama Buddha’s final liberation state, so Jainism does not make a certain claim about it.

So the safest Jain answer is: it is not confirmed in Jain doctrine that Buddha attained moksha.