Basically the same ending or objective as Ash at the end of the trip
No one was satisfied with his current strength; and they continued their travels looking for ways to become stronger and better.
In the case of Red; He isolated himself from everyone he knew to train in a hostile environment (with dubious results since he later lost to the protagonists of other games who were more inexperienced than him)
And in Ash's case; seek new challenges; styles and adventures around the world (despite already basically having all the dynamics; and the title of the strongest in the world)and It's hard to say if Red really lost to any of those protagonists, since, if he did, you'd think it would be mentioned considering his status as a legend. Red gets put on a pedestal a lot which makes me think what you experience in your gameplay doesn't fully represent what actually happens in the lore. But then again, every single Pokemon game file is also its own separate timeline, so there may be timelines where Red has won or has lost. Training for a long time a mountain and having it be completely worthless just doesn't sound right honestly. Doesn't make much sense from a logical standpoint.since really the whole who won in the fight against red and gold is simply up to interpretations
by Physical_Current_858