RoonServer High CPU and RAM Usage Ubuntu 22.04 / Roon Remote slow / no response

can you try with:

DOTNET_GCRetainVM=1
DOTNET_gcServer=0

?

I think you got this right already, but I want to try to answer anyway.

When making changes using /etc/environment, you’ll need to reboot, then attempt to use Roon “normally”, and see if physical memory usage seems to grow to consume all available memory on the machine.