Problem Huawei Y7 2019 resolution


I bought a Huawei y7 2019 and on you tube it doesn't show the 1080 resolution on the whole screen but a maximum of 720. It's not about the video as on other phone models it shows 1080 but not on this one. How do I make it so that it doesn't even tell me on you tube to switch to 1080. All are at maximum 720. Why?