For example, I fill toilet paper rolls with R-candy and or black powder and enjoy watching them disappear as they twist and turn chaotically out of sight (And I make them explode at the end)
I am pretty sure this is not a topic we will be discussing here. Discussing the formulas for making rocket motors is an advanced topic and is only done in a restricted forum. Sorry.
What you are describing is more like a fireworks-style rocket. Some form of safe recovery design is required at organized launches. Chute, streamer, tumble, helicopter, etc.