How to enable only invitations

[discoverlance-com]

To enable invitations, I need to set SENDPORTAL_REGISTER=true in my .env file.

This works alright but the issue is that now, the homepage shows a register link for a user to also register which I don't want. I want to be able to do the invitation but I don't want there to be a public registration page. So it's more or less registration by invites only.

How do I achieve this?