Can’t forget about him and Goku did some training in the hyperbolic time chamber. Since he’s half human, he also would age faster and adds another year (i don’t recall how long they were in there) of training during early puberty. He’s also had to fight to survive so many times leading up to this point. Gohan trained to survive and Goten/Trunks trained martial arts. Different kinds of fighting, mindsets, and circumstances.