To create a custom field using emojis to simulate a rating/score field, you can do it using the following site that lists the emojis available:

https://unicode.org/emoji/charts/full-emoji-list.html

So, in your solution entity create a new Option Set Field, copy the emoji and paste it in the items like this:

 

Add it in the entity form and tried it:

 

You can add it the Grid too!

Enjoy it!