Problem Xiaomi mi 9 downloads very fast


Hello! I have a xiaomi mi 9 purchased in February 2020 from PC Garage. I have a 2 year warranty on it. The problem is that the phone has been charging very quickly lately. Even at the beginning it wasn't brilliant from the battery point of view, it still has 3300 mAh, but I managed to get 6h SOT. Now it lasts me around 3 hours until it reaches 20% when I charge it. Do you think the battery can be changed under warranty from PC Garage? I am aware of the fact that over time it wears out, but the phone is exactly one year old and already the battery lasts 50% less than when I bought it. I only used it with the original charger, a maximum of 5 times in the car, on a charger that outputs 2.4 V, but with the original USB cable. Thanks!