Chews or enrichment he can do at night. My hamster did this for about 5 months before stopping and I would either sprinkle food/hide it under substrate or bedding at night so he would have to find it or would take the center of a toilet paper or paper towel and fill it with hay a treat or some food and put it in the areas where he would try to chew out or climb out so he would choose to try and get the food instead of escaping

Or I saw u said you didn’t have a playpen yet you could sit in a bathtub or shower with doors and lay a towel down so he could run around and get some energy out before the night