I don't understand what you're trying to say here. Is the methodology they're using outdated? Or perhaps their approach seems naive? Or are you saying something else?
And i'm far from being an expert in GCs, but the basics are just wrong.
GCs before ~2010 have been optimized for throughput more than for latency. Since then, you can choose.
Since 10 years, G1 let you set your maximum pause time and you get a huge warning if it miss that target, ZGC or Shenandoah are from the beginning latency first, throughput second.
Like your handle, too.
It is also quite ironic that they paid for Zing C4, and then came up with "P90 average RPC queue time" as the metric, ignoring Gil Tene's wisdom that you should never average percentiles.
Another problematic statement is this:
> which in turn decreases request latency and increases throughput
Gil Tene wants you to measure p99.99 or pmax, so that you will pay for Zing C4 to get lower tail latency, while sacrificing some throughput. If you end up getting both lower tail latency and more throughput, then something is already very wrong with the existing setup (i.e. the full GC).