LightBurn was honestly never intended to be a full creation package, but it’s evolved into one over time. We will be adding support for things like this, but I can’t give a timeline because it’s rather complicated to do.
Open paths just means that your shapes don’t meet at the start / end points (or they’re just not joined). Go to Edit > Select Open Shapes and LightBurn will select them for you. You can also try automatically joining them by using Edit > Auto Join (Alt+J) after selecting everything.