Google Chrome color above the toolbar changed to gray

I suggest that you contact Google Chrome for iOS/iPadOS developer support team, and ask them (there should be a Chrome setting option, but I do not use that browser on my Apple devices).

See also this support page:--> https://support.google.com/chrome/answer/95346?hl=en&co=GENIE.Platform%3DiOS

Regards

Giulio

A browser toolbar is often shown black when the browser is operating in its Private Browsing Mode - and grey when used in its normal (i.e., not Private) browsing mode.

Google Chrome entitles its Private Browsing mode as Incognito Mode.

https://support.google.com/chrome/answer/95464?hl=en-GB&co=GENIE.Platform%3DiOS