I understand that your iPhone display is showing in black and white, and I'm happy to help. This setting has been moved since the instructions that you posted. Try turning off Color Filters as described here:
Go to Settings > General > Accessibility > Display Accommodations.
Choose any of the following:
Auto-Brightness: iPhone automatically adjusts the screen brightness for current light conditions using the built-in ambient light sensor.
Invert Colors:Choose Smart Invert or Classic Invert. Or use accessibility shortcuts. Smart Invert Colors reverses the colors of the display, except for images, media, and some apps that use dark color styles.
Color Filters:Then turn on Color Filters or use accessibility shortcuts. Tap a filter to apply it. To adjust the intensity or hue, drag the sliders.
Adjust the display settings on iPhone
Cheers!