To prevent overheating, you can set up a timer to your bulbs or set up a thermostat, however those are quite expensive. What wattage are your bulbs? I would also reccomend not just leaving fruit in there for your beardie, for two reasons, it will rot and two beardies need to be provided with fresh salad daily. If the dubia roaches you have left in there are live, they will most likely hide and scatter under the substrate or your beardie will eat them all in one go and will not have any food for the remaining days. Considering his age, he needs to be feed daily, so you could work out some options with your roomate, such as transfering the bugs to a cage via tweezers or a toilet role.
Edit: sorry my mistake I thought you said overheat
