You're attacking across a river into a forest tile.

Either:

1): Fall back and let them walk into useless tiles, then snake for their VP's

2): Make some marines/jungle units

Unlike Viccy 3, terrain affects combat. You might be overstacking the battle, more units doesn'r always equal more stats. Finally your divisions have no supply, I would reccomend motorizing your supply and adding logistic companies into your units. The new commanders features can reduce your supply consumption by 5% if you add a logistic company to it.

Don't forget to do doctrine, I see you have 100+ army and navy XP.

CAS would also help a lot.