I can’t seem to build a fully optimized unit and constantly have to make adjustments.

I’m about 20 hours into the game. My units are around level 17–18 on average. No matter what I do or how much I try, I can’t build a perfect, fully synergized team with the right equipment that can dominate everything or at least only struggle against the toughest enemies. I keep having huge weaknesses against certain enemy types.

My main unit consists of Alain, an Archer, a Thief, and a Cleric. The Thief is in the front row, the others stay in the back. Alain protects the Thief when he doesn’t have the Evade ability or when facing enemy archers. But sometimes my whole squad gets completely destroyed.

What do I need to create a strong, well-rounded unit? Is there any sort of guideline I can follow to track this properly?