Maddening, combat units suck

Playing my first playthrough, so fixed growths, have played hardest difficulty on other games (lunatic+ awakening, maddening 3h, fe11 hard 5 etc) but have never felt this level of player phase uselessness from my units. I mean i have exacly two units who can reliably kill things on player phase and it made chapter 23 really, REALLY hard (still beat it tho). Could yall give me some general unit building tips so that i can figure out if im missing something here? No dlc btw