Crouching behind sandbag barricades doesn’t really provide cover for your character, providing a fasle affordance: the recognizable icon of sandbag barricades, but them not having that functionality.
This also relates to these posts, but more specifically so, because some cover does indeed work.
Cover in general doesn’t work at all. Enemies can still shoot around it unless it’s cover you can stand upright behind… ie a wall. Every shooter in this game is a fething wondershot marksman with a 2cm spread at 500m.