What if Steve had gone to Titan with Tony in Infinity War?

The issue with the Titan battle was that it was being directed by two haughty individuals who were unwilling to cooperate. They were destined to be dysfunctional with a team that had such a wide range of fighting techniques.

You can see Iron Man and Star-Lord mirroring each other's positions during the negotiation. None of them were prepared to set aside their egos or act honorably by remaining cool and collected.

Captain America is a take-charge leader, and war strategies are frequently left in his capable hands. People who are familiar with him have come to the conclusion that he is the ideal leader to follow. In essence, Star-Lord would engage Captain America in conversation rather than Iron Man first. Where Quill would get a strong sense of leadership from him. Either that, or Peter Quill would be familiar with Captain America because he is Earth-born and possibly a fan.

In either case, I believe Quill would see his lack of authority. Iron Man and Star-Lord would certainly provide suggestions to Captain America as he would develop a strategy. It would presumably come to the same conclusion, with Thanos becoming stuck and brain-entangled.

Still, Quill would approach Thanos in the hopes of learning where Gamora is. At this moment Cap would be helping Iron Man and Spiderman in trying to take away the gauntlet from Thanos.  Captain America would then step in since he would quickly see that Quill would have become overly emotional and would ruin things for them. While the other Avengers would be trying to keep Thanos in control, Cap would be handling Quill emotionally or maybe violently.

Even one person may have had an impact, especially if Captain America had been present because he would have set the bar the highest. He has an excellent tactical mind and is someone who can quickly predict what other people will do.

They might have been able to triumph on Titan itself if Captain America had been present.

This obviously demonstrates how a newly formed team would function with Captain America absent. Iron Man was not in the right frame of mind; he had always battled alongside Steve (their leader), and all that stood between him and the Avengers he needed were an inexperienced youth, an arrogant sorcerer, and a strange team.

Remember that Captain America did not prepare for a combat against Thanos and that they were concentrating more on the struggle against his army. This is important for those who would argue that Cap's crew in Wakanda was also beaten. Additionally, Black Panther led the battle, not Captain America.