2025 CADILLAC CT5 Visibilitywiper Problems

I went to test drive this car on Saturday 9/27, and noticed that the rear view mirror--the actual mirror, not the video screen inside it--was vibrating/shaking immensely as I drove it. I told them I'd buy the car, but they have to fix the mirror. Tuesday 9/30 I bought the car, with the assurance that the mirror had been fixed. Apparently there's a screw that was loose. Upon leaving the dealership, I discovered that the shaking/vibrating hadn't gone away--it was merely diminished. I took the car back. We discovered another identical model and year of the car on the lot, and it exhibited the exact same problems. Initially the same screw was loose, but after fixing it that mirror also gave the same shaking/vibrating. We determined that this looks like an overall problem with this model and year, at the least, and the dealership didn't know what to do. I...