CMS field designed as a checkbox?

It sounds like you’re just talking about a visual representation, not a functional checkbox.
You can just create your rich text field, and populate it with an unordered list e.g. recipe steps.

Then setup your list to display with custom bullets.

There are a lot of examples and cloneables around this so I’ll link a few-

etc…

https://www.google.com/search?q=custom+bullets+webflow&oq=custom+bullets+webflow