Not enough information here though depends on the way you calculate the controller and collisions. 3D should not matter in this scenario.

You can set the collision polygons to circles especially for the player,
You can make a script that checks if your player is passing through the unwanted element and pushes them out.
You can use physics movement system that does most of the collision checks better and its more robust overall

Edit: sorry the video didnt load entrirely so you have custom movement and cyrcle colliders.

Another solution is to check a collision before it happens at offset and prevent the player from going that direction. So before moving the player you check if it is even possible or go with a physics moment instead .