Fighters killing ships has been a sci fi staple of the last 50+ years, with both missiles/torpedoes and also with gun type weapons.
There are several weapons already that are quite good at fighter killing: Flaks, Devastator for AoE, accurate weapons like railguns and phase lances for picking them off at range, and then closer ranged dps guns like vulcans , light assault guns, or dlmgs (better against shielded fighters). Other than railguns, I don't think any of those are considered that OP for ship-ship combat.
There are a few fighter wings that are very tough, like broadswords and warthogs, but most are pretty reasonably shot down. Huge swarms are a big problem, and its both too easy for the play to amass such a swarm and too rare for the AI to be using anti-swarm weapons.