Hello there and thank you for trying out the game!
Game's combat is more deliberat, positioning yourself correctly is part of the game. The sword's strong attack is more of a gap closer so you should stand a little bit away from enemies when using it. Some weapons like spears will only hit where your spear's tip is, but yeah, not spamming your attacks and making sure they hit is part of the game.
Big guys have super armor yes and that's what they usually gonna have. That's the kinda stuff you'll figure out and learn as you play.
Game is still in a very early development, different weapons , skins and movesets will be in game. This is very barebones to see how people like it and get feedback early.
Thanks again for playing and trying out the game!