The biggest misconception in the chameleon-keeping hobby is what "happy colors" truly are. A chameleon that is truly content is a chameleon that is relaxed. A relaxed chameleon will have duller colors than the pictures posted by Kammerflauge or any other reptile breeder. Most people conflate a happy chameleon with "fired-up" colors that look visually appealing.
A chameleon that is showing off bright, beautiful colors is a chameleon that is not relaxed. They show off these brilliant colors to attract a mate, to fight off rival males (which can be mimicked by showing them their reflection in a mirror or camera lense), or when simply feeling threatened. When their colors are screaming with beauty, think of them actually screaming or yelling. They are not relaxed.
The problem with marketing chameleons by posting pictures of them fired up is that not many people know that the chameleon will not have these colors 24/7. These photos are purely used to sell chameleons.
No one should be trying to get their cham to show insanely bright colors. A relaxed chameleon is a chameleon that will live a long life.
I can add to this later if needed. Also, feel free to ask questions, but it sounds like your cham is doing well if he isn't fired up all the time. You can create a separate post if you want us to go through your care parameters to make sure everything else is on point.
This is not to say that your cham will never fire up naturally. It will happen, but it won't (or shouldn't) happen frequently.