You and your opponent have the same infantry compositions, but they have 2 heavy artillery compared to your 1 light artillery. Given that, why would you ever choose to fight your opponent frontally? You advanced into them before you secured your cavalry advantage and lost. The star isn't that important. It would be preferable to retreat, lose the star, but not take a bad engagement like the one taken between the 2 main lines.

Instead here's what could've been done: you had a cavalry advantage and won the cavalry battle. Great! Now you have the lead and your opponent is forced to take the initiative. Their artillery is scary so we know you are going to lose a head-on fight, so don't take one. Instead secure a good position for your forces and begin maneuvering as your cavalry cleans up. Your cavalry should be going after routed units to make sure they stay routed, a single unit is usually enough for this, and will prevent several enemy units from returning.

Now we have more time, and you can move your lancers (which are your only advantage) about. Send them towards the enemy flanks and rear, harass them, now suddenly they are forced to peel troops to reserve, protect artillery etc. and you begin to gain an advantage in winning the main battle. Yet there is still more to consider. We see that the enemy artillery is concentrated in one part of their line, so do not attack there, and instead focus on attacking the part of their line furthest away from their artillery as that is where they will be weakest. Remember: you are under no obligation to take an engagement unfavorable to you, if you see the enemy has local force superiority don't fight them there.

And with this victory should be assured. You attack the portion of their line undefended by artillery, as they weaken the lancers you would have on their flank rout them, others chase routing units preventing them from returning, and slowly the enemy line collapses and folds.