I suspect you have excessive backlash in your linear module personally
Holes being the wrong size can be attributed to anything from slicer settings/limitations to filament diameter to overextrusion or under extrusion or many other things,
but having a hole thats not round is a big red flag (assuming it is horizontally printed)
regardless, On luban you are a bit limited in corrective actions, but other slicers have a lot of things you can use to compensate with.
There is another setup test you can do without evolving to cura though
Try the linear advance section of this guide
Teaching Tech 3D Printer Calibration (teachingtechyt.github.io)
This test will show you how unevenly the line thickness is on the extrusions, and then allow you to fine to a value to make it better.
this test had a night and day transformation on my print quality.
Additionally, maybe you would be interested in trying an alternate slicer to see what power it can unlock. I made a short video for a member that you might benefit from:
What are the rules of thumb with various calibration and 3D print settings in Luban? - Getting Started - Snapmaker: where creation happens