Im not sure if this would work for you but i had a similar issue with door molding. I placed the sensor perpendicular to each other rather than parallel and the sensor still reported accurately if it was open/close.
I have tried with lowes contact sensor promo here Back again! Iris motion and contact sensors 33% off buy 2 get 1 free + Rebate? as well as the mydigitaldiscount.com contact sensor $10-14
I haven’t tried with Smartthings contact sensor but i think it would work too.