I have ever experienced a similar situation in my VisualTestingInKatalonStudio project. I saw, my project in Katalon Studio ran too slow, consumed too large memory, eventually stopped while processing large number of URLs and writing hundreds of files.
- https://github.com/kazurayam/VisualTestingInKatalonStudio/issues/14 — verbose Step Execution Log out of Test Case script made my test dull
- Log Viewer results significantly delayed — move the code snippet out of Test Case into Keyword, then no more verbose logs will be emitted.
- https://github.com/kazurayam/VisualTestingInKatalonStudio/issues/13 – a lot of output streams left unclosed caused memory leak
I changed my codes and, yes, I could solve it. My code now runs far faster than before, requires fair size of memory, never stops. The tool should not be blamed. God dwells in the details of my code. 
You disclosed your code above. There I find 3 essential points to be improved. I would tell you what.
… still authoring