Question:

Why are all the colors on my screen showing up as black and white?

Answer:

If you've turned on Wind down mode, your screen will display in black and white tones. Check if this mode was accidentally enabled by going to Settings > Digital Wellbeing and Parental Controls > Wind down. Wind down makes your screen gray scale and silences calls, alerts, and sounds before bedtime.

Gray Scale: Changes the screen colors to shades of gray.

Do Not Disturb: Silences incoming calls and notifications, allowing selected exceptions.