Painted over, silicone or flat rail, everything works. My problem: when I look at the front of the end face, it is thicker at the bottom because the drywall on the bathtub side is to be tiled up to 1.20 m. I fear this thickening will bother me.
Alternatively, tile the entire wall 2.10 m. Then everything is the same thickness.
I'll let @ypgs's picture have an effect.
The Quadec should really be used sparingly, otherwise it will be an expensive affair.