What RN7 model variant do you have? Is it M1901F7H or M1901F7G? The G variant is slower since it doesn't have LTE Band 28. Aside from that, your internet connection speed depends on various factors such as the time you're using the internet, proximity to the cell tower and the number of users connected to that tower and using it at the same time and finally your location if your mobile provider is available in your area.
src : David J