If you want to improve your defence just start blocking more and focus on what your opponent is showing you. Let’s say you get beaten up by a Leo player. Watch the replay and write down the moves they where using since most Leo players use the same moves but in different ways. Go to practice mode and practice punishing and ducking the strings and moves that they where using. Can you step the move? To which side? Is it punishable? Can you duck the second hit of the string? If there’s a mid extension, can I fuzzy duck it? Use those questions and learn about the characters key moves and their weaknesses. You can also watch character defence and punishment guides. A great channel for this is Pencil. I wouldn’t recommend it to much because the videos go over so many moves to defend against and most players don’t use that many moves and that’s why replays are good. But if you have no clue how to defend against a specific move you can look through one of his videos and find the solution.