Customer portal communication without email

It would be great to be able to use the customer portal without the email function.

Communicate with customers on their ticket with external comments, rather than sending them emails.

We do not want the customers to receive any emails whatsoever.

Any workarounds for this?

I found a workaround to avoid sending emails to the actual recipient while still making the conversation visible in the Customer Portal.
All you need to do is change the recipient in the conversation to yourself, the support channel you’re currently using, or a no-reply address associated with your account. This way, the system officially sends the email to that address, and because the conversation remains stored, it will still appear in the Customer Portal.

Please see the screenshot and test it yourself.