Hello! I have a vent cover like object that has a collider. I want the player to be able to get through the collider. But make the enemys unable to. How do i do this?

Place another collider in front of vent cover and Check tag if player found then Check IsTrigger option to true on the vent cover collider and unchecked IsTrigger option to false when enemy(tag) collides with the collider.

Collider.isTrigger = true;

Other way is that check distance from player and when player comes near to collider check IsTrigger option to true otherwise make it false.

If your characters are moving using some AI then after trigger you can stop moving that they not pass from collider.