I was told that your receiver can't do 4K is going to be a different model than the d9865
Whoever told you that information is selling you fake content. There's a firmware upgrade that will be provided by satellite soon for the 9865 that includes H265, HEVC, with symbol rates up to 45000. This upgrade is due to programmers migrating to a newer compression needed to be able to make most efficient use of bandwidth available with the reduction of transponders available with 5G clearing.
The 9865 is not going away, in fact its getting better. When the time comes Rainier will contact its current subscribers about getting a satellite delivered firmware upgrade for their receiver. You will need a current subscription to participate.
As far as 5G goes using c band frequencies, this is a very stupid move by cell phone providers. C band is a microwave that can't penetrate cars or buildings. It blocked by trees and other structures in its path. They will learn the hard way that is not going to provide the coverage they expect. The health hazards of high powered transmitters at 3.7ghz microwave frequencies will lead to all kind of problems in the future for people. But they don't care about you. Its all about a money grab trip that will cause health issues for these greedy executives too.