Exactly! And that's where the second 'life changing' event happened to me.

In the settings of my phone I used the 'accessibility' (acc) menu for the first time. And there it was: Grayscale!

Further I have an option to enable a shortcut to the 'acc' menu. This button hovered above my screen, which wasn't nice.

But then, I found an option to put this button next to my navigation buttons (!) 🤯 .

But wait, there's more: I could even customize this button, so it can be used to directly change from gray to color and vice versa.