Jiren is the same. Any true man would find such a towering wall to be glorious, appealing, resplendent. They would be grateful merely to have the chance to face such a thing. Goku and Vegeta are these men, but for different reasons, as we will touch upon. That is why they fight Jiren, without stopping to bawl about “B-b-but WHY is he stronger than my SSJBKKX1000”, they simply act. To men, there is the beauty.
Jiren himself understands that he is nothing more than a wall to his enemies. That is where he differs from previous nemesi of the Dragon Ball chronicles, such as Freeza and Cell. He does not gloat, he does not taunt, he does not plot. He does not sadistically revel, he does not strive to prove anything. He has no need for such things. To the emotionally frail, his stoicism is an affront in of itself, rather than something to admire. “WHY are you so quiet, tell me of your motives and feats,” comes the ignorant babble, and they are left with what they deserve. Nothing. Jiren is here for you to fight, and nothing more. And what man does not find joy in the hunt itself? I’ll tell you, these would be the also-ran of life.
Jiren’s cold front is sufficient antagonism on itself to a real challenger, as one should strive to break it and prove themselves worthy of his true strength. And the two aforementioned characters, Goku and Vegeta, both achieve in doing so. Let me close with the final point, the beautiful relationship between Jiren and the SJ warriors that went over the heads of so many.
Those not paying attention to the internal struggle of these three would claim “Jiren only developed a personality in the final few episodes”. They do not understand that the unblinking, unwavering face of Jiren we were treated to earlier was PART of why the finale was so rewarding, that our protagonists were able to form a deeper connection with such an unyielding foe. They do not understand working towards a goal, instead demanding rewards given.