I've also been asking for months and was told it is not in the current plans. They told me to leave Visible for one month and then open a new account with a new email and activate my phone with eSIM. This is a good way to lose customers.
Other carriers allow for this change and you can do it with an iPhone under settings, cellular, add cellular plan, convert cellular Plan, convert to eSIM. Visible needs to add this feature soon.