Xbox(s) download speed much slower then any other device on network?

Not sure if this is the right place for this but I have asking every other place I can think of already.

My internet downloads at a consistent 25 mb/s on every device in my home except the two xbox one's we have. My Series X is wired to the router and my sons is wireless to the router. As I said every device tests at a speed of 25 mb/s but the two xbox's consistantly
test at anywhere from 3 to 5 mb/s. This is very frustrating because the majority of our downloading is on the xbox's! I have tried power cycling the xbox;s, I've power cycled the router, I have tried setting QoS on the router and I have cleared the cache on
the xbox's. Nothing has worked. Can anyone please help me?

:)