Your phone is probably using the 5 GHz band when close to the router and 2.4 GHz when you move away. The latter is slower but has a greater range.Windows desktop PC and laptop both have excellent wifi downloads. iphone11 in the same room is much slower, Is this to be expected when comparing desktop with smartphone. iphone download is excellent close to the router, but drops off very quickly.
Yes, you would need to go to your router settings.Thanks for that. Is there any way of seeing which band the phone is using at any time?