There was a similar problem, check this topic.
Most likely you have network issues, not just the lag like FB processing speed.
As Leandro Jedi said, remove stdin and stdout, especially debug because it consumes a lot of resources.
Since you are using different version, make sure to us the same version or at least upgrade FB. This is not mandatory, of course.
Since I have a high volume of logs and a single Logstash instance with many cores, I configured multiple listeners to avoid a single TCP thread bottleneck at the input stage
Why don't you use LS pipelines? Separate .conf files. Maybe even you can use much faster the dissect parser filter in some cases.