It is not that there is no ultimate truth, but rather, that there is no closet which might contain or fail to contain “ultimate truth”, it’s just the word “truth” with the sonorous-sounding adjective “ultimate” tacked on in front. Truth is all there is or coherently could be.
So what about the Ultimate Showdown of Ultimate Destiny?
...sorry, couldn’t resist.
But there is a truth-condition for whether a showdown is “ultimate” or not.