Again you are missing the point
Tony only found it because he was hesitant at first about the whole time travel plan the others had
If the other Avengers didn’t come to Tony about the whole time travel plan this would mean Tony wouldn’t have found a way to stabilize time itself
Plus the only reason why Steve, Scott and Natasha came to Tony because Scott had an idea about the time travel when he was in the Quantum realm
And the only way Scott was able to get out of the Quantum realm because the rat ran over the control plan that released him
No one else was around since it was in lock up. so basically everything else that leads up to Tony figuring out how to stabilize time was because of the rat
Everything else factor in because of that one thing that happened