Issue: Cannot run multiple concurrent sessions on the local machine
Firstly, the root cause of this issue comes from the RAM capacity you have. For the concurrent executions (and execution with Docker), the number of concurrent sessions should multiply by 2GB. For example, recommended RAM for 3 concurrent execution sessions is 6GB (3 x 2GB). Please refer to this guide for details
Besides, the execution of multiple tests in the same project location is a bad practice and Katalon doesn't support this way.
Therefore, for a solution, our development team recommends you use Jenkins as a CI/CD tool that can help you with executing multiple tests at the same time since Jenkins can help you with checking out the repository into the folder relative to your workspace. This way you can have as many repositories in your project as you need, all in separate locations.
Please refer to these guides https://www.jenkins.io/doc/book/pipeline/jenkinsfile/#using-environment-variables
and the attached images for samples