Anonymise form submission

Hi,

I have a form which fills a sheet with an "Anonymise" checkbox column and a "Submitter" text box column. (staff feedback form)

I'm trying to give form submitters the option to anonymise their submissions. At the moment, an individual has their own link which will auto-populate the submitter on the form but want to be able to change that value to blank if the anonymise checkbox is selected.

I don't want to make this a dropdown (as then a submitter could respond under another person's name).

Can I use a formula to make the Submitter field become blank at the time of submission if the 'anonymise' checkbox has been checked?

Or is there a better way to do this?

Thank you,