I would try and lower your ambient temp in your room. 70 is good. 75-80 seems to high to me.
Some chams really feel comfortable with the stick method that Laurie mentioned. I have a panther Cham who despises it. He must think it is a snake because he puffs up huge at the first sight of the serpentine dowel hahaha.
Each Cham is different. And they are shy by nature. You will just need to take your time and be patient. When I first got chams, I heard stories on here about chams running to the screen to be let out. My first two were not like this, quite the opposite. I worried that I had done something to scare them into their defensive behavior. One of them calmed down with age, even though he prefers not to be held. I had to learn patience because I wanted to have them out on me all the time. When I started learning more about them, I started allowing them to make the moves, with food being the great motivator.
I stated using supers. My chams go crazy for them. Try this the first meal of the day when they are hungry. Put a worm on the flat of your hand and present it slowly. Usually they will be a bit nervous of the situation but should settle in a couple mins. What their eyes, if they are scanning for an escape route, you probably moved to hastily. If they slowly become interested in the bugs movement and then fixate, you have made good progress. I just kept doing this, luring the lizard more and more onto my hand. All but one of my chams will hand feed but that doesn't mean they will come onto your hand. Just be patient and never get frustrated and force them into anything they don't want. Slow and steady. And young chams do mature and become more chill.