Add an auto complete drop down to the edit form of a modern team site list

Question

We have a requirement to replace a field in the edit form in a SPO modern team site list with an auto complete box. The data needs to come from a public REST service. I can see there is a Customize forms button that navigate you to the power app form. Is it possible to add an autocomplete field, or will that result in CORS errors? Or is there other implementation options?