Where do I suggest new emojis?

I don't think Apple creates emojis.

If you have some suggestions or proposals then you are free to provide them here --> https://unicode.org/emoji/proposals.html

you can suggest it to the international unicode org

Guidelines for Submitting Unicode® Emoji Proposals

it's them not apple who handle the emojis

no, for emojies to be multiple platform rather than apple devices only the international unicode org handle it

if you want to know more Unicode - Wikipedia