Adding iCloud to Gmail app
Took me forever and was very frustrating (because even after speaking with an Apple agent she had no idea what I was talking about) BUT I finally figured it out!
Firstly go to apple and they will create you an app-specific password that you will need to screenshot or write down before you lose it. (very long)
Secondly, even though the apple website itself says to enter your full name NOT to enter your icloud: enter your iCloud email because that’s what worked for me. It should say
Username: abcdefgh@icloud.com (example)
Then insert the app specific password from earlier into the password section.
Lastly, I left all the other information alone.
iPhone 15, iOS 18