After updating my watch display going like black and white

It looks like our moderators have moved your question into the Apple Watch area.

In the Watch app on your iPhone go to My Watch > Accessibility > Colour Filters and make sure

(a) the Greyscale option is OFF (you might have to temporarily turn filters on)

(b) The main Colour Filters option is OFF unless you need it for other vision issues.

You can also get to it direct from the Watch screen, but the iPhone app is easier to use.

This is the macOS Ventura section you may get an answer in the Apple Watch section but make sure you give full details in your question.