Warning! Spoilers for Doctor Strange 2 ahead.
Doctor Strange put up a good fight against Thanos in Titan, so why did he seem so weak at the start of Avengers: Infinity War? Doctor Strange was instrumental in ultimately defeating the alien villain in Avengers: Endgame, as his actions kicked off the series of events that led to the heroes' win five years later. However, when Doctor Strange first appeared in Avengers: Infinity War, it didn't seem like he was capable of much, considering how easily he was captured by Ebony Maw in New York.
Coming into the fight against Thanos, it had just been two years since Doctor Strange's first foray as Master of Mystic Arts. After being in a terrible accident that left him unable to return to his profession as a neurosurgeon, he found other ways to heal his physical body. After learning sorcery can do more than that, he changed paths and became the expected successor of the Ancient One following her death. It's uncertain what he was doing in the two years since he fought Dormammu and the attack on New York by the Black Order but considering how much of a quick learner he was in Doctor Strange, he appeared to be more equipped and knowledgeable in his second proper outing in the MCU.
That said, Doctor Strange appeared to have fluctuating powers in Avengers: Infinity War. In the beginning, he was quickly ensnared by Maw, and had it not been for Iron Man and Spider-Man, the Black Order member could've killed him. Eventually, when he finally faced Thanos in Titan, Doctor Strangeheld his ground pretty well — in fact, he put up arguably the best fight among everyone. He and Thor were the only ones who forced Thanos to use the Soul Stone, and Thor's moment of glory appeared to be largely the result of the Stormbreaker.
Doctor Strange’s Power Level Change In Infinity War Was Strategic
Looking back at Avengers: Infinity War, it's less that Doctor Strange had inconsistent power levels and more that his circumstances in the film changed. Initially, his main goal was to keep the Time Stone safe, and as his primary source of power, he was willing to die for this goal. Thus, he was more careful and calculated with his moves, as he was afraid that it might get swiped from him accidentally.
Later on in Titan, after he learned that the only way to succeed in their fight against Thanos was to be defeated first, he understood that he would have to intentionally give up the Time Stone. With this huge burden lifted from his shoulders, he was able to freely take on the Mad Titan without overthinking the possibility of losing the Infinity Stone. In conjunction, knowing how things will pan out would've given him liberty to fight Thanos the same way he did Dormammu in Doctor Strange. Since the outcome of their one-on-one battle didn't matter in the grand scheme of things, he could do it without pressure.
In hindsight, Doctor Strange may have also used his time fighting Thanos in Avengers: Infinity War to practice some of his newly-learned skills that had yet to be put to practical use. So while he no longer has the Time Stone in the primary MCU timeline, he was more equipped to take Wanda's absurd level of power in Doctor Strange in the Multiverse of Madness. And if he ever re-acquires his primary weapon in the sequel, he'll be all the more powerful
Doctor Strange 2’s Darkhold Powers Show The Other Side Of His Abilities
If Doctor Strange's power levels seem strategically low in Avengers: Infinity War, Doctor Strange in the Multiverse of Madness flips this dynamic to show the terrifying power he's capable of when he doesn't hold back. What If...?'s Strange Supreme hinted at this already, showcasing how Steven Strange is prone to darkness when sufficiently motivated. Ever the strategist, Doctor Strange will use whatever means necessary to accomplish his goals even if there's risk involved. In the case of Avengers: Infinity War, this meant a conservative strategy geared towards protecting the Time Stone, but in Doctor Strange in the Multiverse of Madness, it means resorting to drastically powerful measures, namely, the Darkhold. Viewing the curse of the Darkhold as his best option, Doctor Strange is willing to tap into an unprecedented level of power, even though it also means becoming corrupted. With his MCU adventures far from over, it's likely that future appearances from Doctor Strange will see his power continue to fluctuate depending on his situation, as first revealed in Avengers: Infinity War.
