I'm taking a guess here and after spending tons of time looking through the sound tracks, I think its "The Strength of the Man Who'll Become the Number One Hero" which is from the second movie "My Hero Academia: Heroes Rising". I know its been a year lol but let me know if I got it! I found it midway through the song roughly. It was the only song I found with it, but maybe I wasn't listening carefully enough to the others.