Single Select with Other Options that user can add their answers?

Does anyone have an answer to this?

In the table, you don’t need an “other” with the ability to type a different option. If your choice isn’t there, you can create the new choice on the fly by just adding it.

Not the same with the Form - your selection must be there. There is no native ability to do this. You can roll your own by adding a field for your “Other” entry, and making it visible only if the user selects “Other” from the single select field.

You can also use an automation to move the ‘other’ value from the form submission to the single select field so that it will be available to future users.