Captain America was frozen for roughly 70 years in the comic books. It was a key element of his character's story, shaping his perspective and challenges when he woke up in a much-changed world.
Aang's age in the comics varies depending on the specific storyline, but generally, he is depicted as a bit older than in the original animated series.
In most of the comic series featuring Aang, he is around 12 to 14 years old. This age range is maintained to continue his adventures and growth as a character.
He might start by observing. Aang is a curious person, so he'd likely watch how people live, how they interact with technology. He may also try to find other benders to learn about any new developments in bending. And he'd probably use his kind heart to make friends easily in this new future environment.
Aang might go into a deep state of depression. He has always been an emotional character, and having his heart broken by Katara, someone he loves deeply, could send him into a downward spiral. He might isolate himself from his friends and stop practicing his bending for a while.
In some fanfictions, Aang's connection to his past lives plays a crucial role. He could draw on the wisdom and skills of previous Avatars. They might guide him on how to defeat Azula specifically. He could learn a new bending technique from one of his past lives that gives him an edge over Azula's firebending, like a unique way of using water to extinguish her most powerful fire blasts.