The ending of the Infinity War comic is quite complex and full of surprises. Thanos achieves his goal initially, but there are unexpected twists and turns that lead to a dramatic conclusion.
The ending of Avengers Infinity War is important because it's a major turning point. It makes the audience feel the real threat of Thanos. By having half of all life disappear, it shows how powerful and unforgiving the universe can be. It also gives a strong motivation for the Avengers to fight back in the sequel.
Well, at the end of Avengers Infinity War, it's a real downer. Thanos gets what he wants. He uses the power of the Infinity Stones all together. Bam! And then, just like that, so many heroes disappear. It's chaos. The remaining Avengers are just standing there, stunned. They've lost so much. It's a huge turning point for the whole Marvel Cinematic Universe and sets up the big fight for redemption in the next movie.
One possible alternate ending could be that Doctor Strange actually manages to defeat Thanos using his magic before he can snap his fingers. Strange could have found a way to trap Thanos in a time loop or a different dimension, thus preventing the mass destruction that occurred in the original ending.
A really interesting scenario could be where Thor aimed better when he had the chance to kill Thanos. He could have ended the whole threat right there. If he had struck Thanos in the head instead of the chest, the events of the snap would never have occurred, and the universe would have been saved from that mass destruction.
Doctor Strange could be the key character. Since he had the ability to see different futures, he might have found a way to change the outcome more drastically. For instance, he could have used his magic to trap Thanos in a time - loop or some other magical prison, preventing him from getting any of the stones.
One possible scenario could be that Doctor Strange saw a different future where they managed to stop Thanos before he got all the Infinity Stones. So, the Avengers might have worked together more effectively from the start. For example, they could have sent a team to intercept Thanos on his way to collect the stones on different planets.