I am playing on a Minecraft Realm with considerable lag and disconnects. I noticed that all my upstream traffic was used (if I went to a big cow farm) and I think it is for the same reason as the issue.
May I politly request to consider re-opening this issue?
By accumulating not all but some packages (for example all packages within a 0.05 sec window) one could maybe find a solution without lag but greatly reduced package count. (1 package per 0.05 sec would reduce the package count in this example from 1000 to 20.)
Furthermore, I think that Mojang would benefit as well, since they pay for the traffic at their end, that is at the server.
I am using debian (buster/sid) with Minecraft Launcher 1.6.89-j. I got exactly the same error messages as far as I can tell. I also tried to remove the VM option and got a "no lwjgl64 in java.library.path" as @Jacob Page. Based on the comment to downgrade to Java 8 (I tried 10 and 11 before) I can confirm that this resolved the issue for me. (Or provides a temporary workaround since Java 8 is not really what I want to use.)