Blocks, in my humble opinion, are a result of resistance towards your "authentic" stutter - the classical repetition stuff. When we resist stuttering, a sort of bodily panic response happens, causing us to block. A few years back, when I decided to let myself stutter freely without holding back, my blocks disappeared. The moment I start resisting stuttering (the repetitive stuff), the blocking kicks in. The resistance is what causes a bodily "panic" response, sort of like fight, flight, or freeze. We often fight stuttering "authentically" because we hate the idea of others hearing us stutter. When you drop the resistance of stuttering absolutely freely, you'll notice a big difference. Hope this helps for you!