how to change color on one screen and have it change on another screen as well?

I want to press a button on a settings screen and have it change the canvas color on  a  different screen .



You need to save the value of the chosen color to a TinyDB and restore the value from the TinyDB when you return to the screen, then set the canvas color from that value.



Not sure of this but, maybe the "Any Item" objects in the blocks editor could be used for this?



no, this does not help

just follow Enis' suggestion