Once unblocked, the person can immediately see your public posts, tag you, and send you friend requests again. The Fine Print
The feature is for those looking to mend bridges or simply clean up their restricted lists. However, users should be cautious: because you can't immediately re-block, ensure you are truly ready to interact or be visible to that person before confirming the change. How to Block and Unblock Someone on Facebook - Security.org unblock person facebook
Whether you are mending a bridge or simply cleaning up your digital footprint, managing your block list is a vital part of curating a healthy social media experience. Once unblocked, the person can immediately see your
(if implemented)
Blocking someone automatically unfriends them. Unblocking them does automatically send them a friend request. Once unblocked, that person becomes a stranger to your account. How to Block and Unblock Someone on Facebook - Security