What is the fastest way to level a new account

My son has been playing with my account for the past month and really liked this game. So I decided to create a new Steam account just for him. This way we can play together. He already knows all the game mechanics by playing with my characters and he did most of the quests up to Yorn. Is there any way I can boost/speed level the new account so that he doesn’t have to redo all the quests and leveling?

Thanks in advance!

With new steam account etc you need to do all again. For punica you can buy a finish quest item but i dont think this item is not worth it.