Belgrado

Hi guys! Fortunately I found a solution to the problem: Use a gigabit switch. 
 
Orange Pi 3 and Orange Pi 4 just work on switch with Gigabit technology fine and not with 10/100 interface. Orange Pi One works fine but as exposed in old topic it was fixed. I found after first update many scripts of NetworkManager modified, maybe there are flags and other scripts impacting on NetworkManager.

We mainly know what is wrong. What we don't have are expensive resources to fix things. At least not with the speed "you" desire.
 

https://github.com/armbian/autotests
https://www.lavasoftware.org/about.html
https://kernelci.org/
 
If you want to do something truly useful for the project, ask what is here to do, not to assume you know what is best thing to do. Perhaps rework this application? You will contribute and learn a lot.