Do you find the game challenging? I'm still yet to win any scenario except tutorials....

Hello, I've tried BotB scenario four times but failed all of them. I can get the advance started but after few days the game just gets too hard. For example, US unit of 3 pips stopped my 4pip armor + 2 infantry with total of 6 pips for 3 turns. I've tried different approaches to attacking but it see...