Iron Man + Spider-Man + Doctor Strange + Mantis + Drax + Quill seemed like they basically beat Thanos with 4 or 5 Stones in Infinity War if Quill wasn't a dumbass. Maybe I'm forgetting someone but that was roughly the group. Nebula might've been there. Anyway point is when the final battle is those 6 of 7 + a bunch of other people vs Thanos without the stones it feels like we're de-escalating a bit, especially since the army scenario was basically the ending of Infinity War.
Anyway honestly I didn't have much of a problem with the scene, liked it even in a "hell yeah these guys are badasses doing badass things" kinda way, so this is kinda nitpicking don't get me wrong. I'm just explaining why I kinda was hoping for a bit more somewhere, why 'just' fighting Thanos kinda stopped doing it for me as much after 2 long movies with a bunch of cool fight scenes.
Them beating him was entirely contingent on Mantis though. Remove her and throw in extra people who are better fighters and they still lose
This, plus they had time to set up a plan and ambush him on Titan.
There was no time to plan in the final battle in EG. He ambushed them, and the only planning that got done was Strange gathering the reinforcements. Given that he had like thirty minutes to gather the Wakandans, Asgardians, sorcerers, and Ravagers I'm guessing he couldn't tell each much other than "Get ready for a big fight with Thanos, gonna open a portal" and that's it. ---