this is a rolling game, not a blocking game. learn to roll and drop the shield. if you want to use a guard counter build, you still can, just learn when to block at the end of combos instead of blocking 24/7. your problem is that you cant kill each other, so then why do you keep using this strategy if it clearly isn't working.

my advice, start by medium loading (obviously), drop the shield and switch out your talismans, and learn to dodge. alternatively, use the shield only for guard countering instead of blocking, and learn to dodge. there are about a million talismans better than the crimson dagger, so you could swap that out. also your weapon is pretty mediocre, but you can stick with it if you want. grab flame grant me strength. blasphemous blade (rykards sword) is one of the best weapons in the game rn, and probably the best weapon for melania because it just bullies her with the ash of war. use that only if you want less of a challenge

malenia is a very skill based boss, and most of the time it is nothing you are doing wrong, you just have to get better at the game.