
He did. a lot of fans don't realise that strange did in fact "use" the time stone. he used it in the smartest and best way possible; not as a physical weapon, but as an insurance and a very powerful tool of sorts. he used it to see 14 million possible outcomes, probably living through every single one of them in real time, which just goes to show how strong strange's mind, memory and will is. he then selected a few in which they won, and chose the one in which they had the most acceptable amount of losses and casualties, i.e. tony and nat and maybe a few more dying. maybe in one of the universes in which they "won" almost everyone was decimated. so strange chose the best possible option (deemed by him), and then proceeded to very carefully place moves and actions to determine their win in endgame. from the moment where he viewed the futures, to him intentionally losing to thanos (yes, he intentionally did it), all the way to the rat in endgame, and the final battle. when thanos finally yeeted carol out of existence, then strange saw that all of the pieces were in place, and every corresponding piece matched up with the winning future he saw, and all that was left was for tony to make the choice. every piece was a gamble, even betting the fate of the universe on the rat. strange played chess with the fate of the universe, sacrificing (chess move) his loss against thanos and giving up the time stone to gain a tactical advantage 5 years later. in my opinion, i believe that strange may be the most powerful avenger, not because of his mind and magic prowess alone, but because of his will and determination to see it through. even going as far as to bargain with dormmamu for what could have been eons, and living through every single one of the 14 million futures.
In short, Strange is wise.