It seems to be a feature request on user voice only
ability to disable Wildcard certificate option in Let's Encrypt
But it would indeed be very important to be able to disable this feature. It is not only causing many additional support requests by customers who see the option, but get an error when clicking on it (as the DNS module is not installed), but it seems to cause issues when updating extensions, too. We are now occassionally seeing update installation error messages on extensions claiming that the Plesk DNS module is not installed and the extension requires it to work properly. The only extension that can be meant is the Let's Encrypt extension.
So all in all, I think it was not such a good idea to not to provide an option to disable wildcard support.
ability to disable Wildcard certificate option in Let's Encrypt
But it would indeed be very important to be able to disable this feature. It is not only causing many additional support requests by customers who see the option, but get an error when clicking on it (as the DNS module is not installed), but it seems to cause issues when updating extensions, too. We are now occassionally seeing update installation error messages on extensions claiming that the Plesk DNS module is not installed and the extension requires it to work properly. The only extension that can be meant is the Let's Encrypt extension.
So all in all, I think it was not such a good idea to not to provide an option to disable wildcard support.