Unblocking can be a sign of emotional distance. They no longer feel the need to block you, but they also don’t want to invite interaction by following.
They might have been unblocking multiple people (e.g., after a breakup or a social media cleanse) and you were just one of many. No special meaning intended. ex unblocked me on instagram but didn't follow me
"Unblocked but not followed" is the digital equivalent of them driving past your house but not stopping the car. They’re looking, they’re remembering, but they aren’t ready to come inside. Unblocking can be a sign of emotional distance