How to customize frequently used emojis on iPhone?

I would love to have a small selection of adult emoji’s that I have selected in my “Frequently Used” emoji list. Instead, Apple has permanently implanted emoji’s like the yellow roundface with hearts for eyes. So many of them that my own, truly frequently-used emojis are below the bottom of the emoji window, where I have to scroll to get to them.

[Edited by Moderator]