Is using a hyperlink to close a modal a poor design decision?

1. Should modals have a close button?
2. Should cancel be a button or a link?
3. In which scenario do we prefer to use a link instead of a button?

Should modals have a close button?

Closing the modal: Always provide a clear close option for users by using a button or an 'x' icon at the top right of the modal.

Should cancel be a button or a link?

To summarize

The cancel option is similar to aborting an action, and therefore similar to navigating back to the previous state of the UI. Navigation is represented in web UI as hyperlinks, and thus the cancel option should be a hyperlink.

In which scenario do we prefer to use a link instead of a button?

There are differences as to when a button should be used rather than a link. UX Movement wrote an article about this, and they came up with a simple rule: Buttons are used for actions that affect the website's front-end or back-end; links are used for navigation and actions that don't affect the website at all.