> I should mention the GC situation was worse until the last few years. Until ZGC and Shenandoah came around, Java still didn't collect frequently but when it did there were long pauses.

This feels like G1GC erasure. I'll also say we've tried out ZGC and while pause times were low, it had a huge CPU overhead and the performance of our application was notably worse and we went back to G1GC. We're still on Java 11, so maybe we'll see some magic when we eventually try the newer versions.