He has been solid as a CB and I agree that he has been getting too much criticism when he has been consistent and likely our best CB this season.
The issue is that he is not a ball playing CB and in these systems, you need your CB to be either pacey so they can chase down forwards when they get behind you or alternatively you need to be solid and have elite ball playing skills. I like De Light but unfortunately, he doesn't seem to offer those attributes so I do think the club may look to upgrade in the medium-term.