Interesting. Have you considered/tried to use fdio/user space networking? In my experience, it greatly improves throughout (simple ip forwarding can be more than 10mpps per cortex a53 on some platforms). Fdio also has a so that you can preload in order to use its ip stack in your app (instead of Linux's).

See https://s3-docs.fd.io/vpp/22.06/developer/extras/vcl_ldprelo...