I’m Struggling with Chronic Heater Issues in My 2016 Alfa Romeo Giulietta

Hello! I own a 2016 Alfa Romeo Giulietta, and although my heater issue isn’t labeled “chronic,” it’s persistent and frustrating. When I took my car to the service center, they weren’t solution-focused. I’ve also tried several mechanics with no success. The problem is that while the right side blows cold air, the left side near the driver’s seat blows hot air. I was told it’s a flap issue that requires removing the entire dashboard. However, this comes with a high risk of noise due to improper reseating and apparently doesn’t guarantee a lasting fix. If anyone can suggest a permanent, effective solution, I’d greatly appreciate it.