This feels more like a system balance issue than a pure LaunchBox problem. With a game already using around 6 GB of RAM, Chrome running video streams, and LaunchBox keeping media and metadata cached in the background, a 16 GB system can hit memory pressure pretty quickly.
Memory “optimizers” do not really reduce usage. They mostly push inactive data into the page file, which can move the bottleneck from RAM to disk I/O. That can explain why things look better in Task Manager but do not always improve real performance.
Using list view, lighter themes, or Big Box helps reduce background memory, but if this workflow is common, upgrading to 32 GB RAM gives the OS enough headroom to manage caching properly. In this case the issue is overall hardware balance, not just one application using too much memory.
You can check the bottleneck of your system first.
The comparison between the different CPUs is interesting, especially since the i5 9600K did not change the behavior. That makes it seem worth separating the LaunchBox issue from the hardware side and checking whether the CPU itself behaves normally under a sustained load. A CPU stress test can be useful for that kind of basic check, particularly when trying to rule out stability or throttling issues.