My cars steering wheel seems to be shaking when slowing down at high speeds. It seems to be slowly getting worse and the shaking becoming more seemingly causing the dash to slightly shake as well. I've already replaced both worn out tie rods and got an alignment. Anyone have any idea what else it could be? Doesn't seem to be anything wrong with the rotors as well.

The most common cause of the steering wheel shaking during braking is the rotors needing replacements. Also possible the calipers need to be dismantled and cleaned up completely to like new condition.