There is a known problem with MAK ONE applications and CentOS 8 running out of memory. When the OS runs out of memory or starts using the swap memory, it can become unresponsive. Here are some potential solutions:
Upgrade the Linux kernel to at least version 5.7. We have found that the default kernel of 4.18 becomes unresponsive when the swap is being used but the 5.7 kernel does not have this problem.
Adjust the terrain being loaded in the MAK ONE applicaiton to have fewer osgEarth layers and simpler models to reduce the memory consumption.
Add more RAM to your computer.