How to whitelist specific IPs to use the REST API?

Hi,
How can I allow only specific IPs to use the WP REST API? I tried the wildcard ... on the blacklist and then specific IPs on the whitelist, and that worked, but the issue is that it was also blocking everyone from registering on the site, and I only want to block the access by IP to the REST API. Is that doable on the free version? Or is that a PRO feature?
Thanks