Since you liked the orange theme so much, i recommend you to change the default background color to a blacker color, hereās a difference, left is changed and right is the default:
I actually use this color on another theme that have a better contrast with it, maybe a color a bit lighter on the orange theme is better, but you can place any color you want, I find the default grey of Krita background kind of ugly, and a blacker color can be easier on the eye
On Settings, go to Display, then on the āGrid Settingsā tab, change the āCanvas Border Colorā to a color of your liking.
But yeah, Krita on Android itās getting awesome indeed.