I get about a mile at 400 feet up less as I go down . I think the best I ever got over the lake was about 8500 feet . with the P4P.
In the trees at 400 feet up about 1200 feet . As I said I have never got anywhere close to what DJI says they will get .
For me, it is quite impressive. I usually start losing connection at 1300 m. I think your distances are high normal. Those distances in manuals are not usually achievable. Anyway, you can not see the drone over 1 km.