Override iPhone's automatic brightness adjust?

Apple seems to have completely removed the automatic brightness switch in recent iOS versions - the only 'automatic' settings now are for light/dark mode & Night Shift.

I don't mind Night Shift changing my screen's white point as night comes on, but in regular daylight I heartily object to it constantly deciding for me how bright the backlight should be.

I'm reading my book, it feels a bit dim for the ambient light I'm in, so I quickly dial the brightness up a bit…. then as I'm reading I can see the system just overruling me & turning it back down again.
So I turn it up… the system turns it down. Rinse & repeat ad nauseum.

I really do feel it's something I ought to be in charge of.

Does anyone know the magic dance necessary to stop it doing this?

Picture of settings just in case I missed something really really obvious.

Settings app will help you find this if you search for Auto-Brightness

The Auto-Brightness switch was moved in iOS 13.

the Source of the images below is this article:

Go to Settings -> Accessibility -> Display & Text Size. Scroll down to the bottom of the page and you will see the Auto-Brightness switch.

From here you can turn off this feature and, hopefully, this battle with iOS will be won!