It's ok to be somewhat cautious until you get a good feel for postflop poker. When it becomes not ok is when you have a lot of losing hands in the villains range that will pay you off, and you default to check call mode instead of building a big pot with a big hand.

Hand 3 is a perfect example. Make progressively larger bets on each street, especially when villain remains passive. There's no excuse for acting like a scared little girl in this hand.

Don't control the size of the pot every hand. If you're too afraid to lose, you're too afraid to win.

Think about what your opponent has for a hand, and bet as if you're certain they hold that hand until you're forced to change your mind. You'll be wrong often for a while, and then eventually you'll be playing poker correctly, because you'll be putting people on hands, and maximizing value.