Unable to use Genmoji on iPhone 15 Pro with iOS 18

See the instructions here, Create your own emoji with Genmoji on iPhone - Apple Support Understand there are restrictions. Read the notes area regarding the restrictions on Apple Intelligence and other support.

Well, you have an iPhone 15 Pro, you have Apple Intelligence turned on and active, you are in a supported region and language, and you have clicked into a text field and opened the emojis. Is that correct?

What troubleshooting have you tried?