Haha gl, I remember seeing a pic of a GDK bot with no other stats but combat, no quests completed, and 26mil xp in atk, str, and def . So with a good enough bot it's definitely possible to go for ages.
Good luck bro. I remember seeing this a while ago. I started up a main a while ago and am working on 126 combat also. I just don't know what to do with the prayer.