When you unfollow someone, the ability for them to see your posts is not straightforward. In the case of Facebook, if your posts are set to public, then even if you unfollow a person, they can still see your posts. But if your posts are restricted to a certain group of people like friends or a custom list, and this person is not in that group anymore (because you unfollowed them), they won't be able to see your posts. Different platforms handle this differently, so it's important to know the privacy rules of the platform you're using.
If you unfollow a person, it depends on your privacy settings for your posts. If your posts are public, they can still see them. But if your posts are set to be visible only to your followers, then they won't be able to see your new posts once you unfollow them.
Typically, when you unfollow someone, they may or may not be able to see your posts. On platforms like Twitter, if your tweets are public, anyone including those you unfollow can view them. However, on Instagram, if your feed is set to private, unfollowing someone means they won't be in your approved follower list and thus won't be able to see your new posts. It's all about how you've configured your privacy settings.