Do what I do, mount your toll transponder stickers on a slightly larger piece of plastic laminate called Stickershield.

Put the sticky side of the transponder down on the non-sticky side of the slightly larger piece of Stickershield then apply the opposite side of the sticker shield to the windshield. I’ve used it successfully to apply and safely remove then reuse sticker transponders on rental car windshields. You just have to make sure to lift from the edges of the Stickershield when removing from the windshield to avoid bending (and thus destroying the sticker transponder internal circuitry).

I have a Kansas K-Tag, Washington State Good to Go, South Carolina Palmetto Pass all mounted on Stickershield.