Trunks and Goten are pretty evenly matched fighters. They both have the Gotenks SSJ3 form which can help a lot in a fight. Of course Trunks’s future form has SSJ3 and so does GT! Goten has……..well Gotenks is enough for him!
Goten just lacks the skills that Trunks has. Trunks did win when they fought in DBZ after all. If they were to have a rematch I have little doubt that Trunks would come out on top. Goten takes his first loss, but he’ll be back one of these days. Trunks wins.