NeetoCal lets you password protect a scheduling link so only people with the password can see your availability and book a meeting. It is a simple way to share a link freely, for example in an email or a private group, while keeping your booking page private.
Access control offers other options too. Make a link invite-only, where NeetoCal sends each listed email its own invite, or allow only emails matching a keyword such as your company domain. You can also limit a link to logged-in workspace members for internal meetings. Once someone has access, they are not asked again in that browser. Intro pages can be password protected as well.