I gather from this that WC is submitting it’s form through AJAX. In that case I would add my own form fields to the WC form and then use the acf update functions like https://www.advancedcustomfields.com/resources/update_field/ to manually update the ACF user fields myself. When using these functions you should use the field key and not the field name to do the updates. You could also use update_user_meta() like in your example but you need to update the ACF field key reference in addition to the meta value, but it would be easier to use update_field using the field keys.
