Without VPN, it slowly loads sites on Android. What is the problem?

Question

Android

The house has a shared Internet on PC and mobile devices. Everything flies from the PC, but on the mobile (Xiaomi mi a1) surfing slows down inadequately. What is strange, YouTube works adequately, however, like other software. Everything except surfing in browsers. Ops does not have this problem. Also, the problem is solved if you enable vpn. What could be the problem?