I have found some weird behaviors at VyOS when doing simple routing.
In a GNS3 lab running on a local computer, there are clearly two different levels of throughput as shown in my attached tests. They also vary depending on the VyOS version.
In an EVE-NG lab running in a Sentrium server, throughput is very different depending on the VyOS version.
I attach a document with all the tests I have done so far, which shows some patterns of those irregular behaviors..