Dreams are not all bright and vivid in nature and it's no different for lucid dreams. I wouldn't worry about it too much as you will find over time it will vary anyway. If you are really eager to increase the vividness of dreams and possibly make them more colourful, try interacting and paying attention more to your environment in a lucid dream (rub the walls, touch the floor, eat things, take a look around). Just get very hands on and pay attention to your environment, and you will start to notice a lot of detail in your dreams.
Looks like you're having good success with supps, I'm glad to hear that and keep up the good dreaming
If you want to try and use them less you could try doing MILD
, which is where you focus on becoming lucid and repeating in your head that you will be lucid dreaming once you fall asleep. There are of course lots of techniques you can use though, but it's best to develop at least one where you don't need supps in case you start to become tolerant of them. If you learn to lucid dream naturally now, you will still be able too when you can no longer use supps.