Where are you located? Maybe there is a Glowforge owner with some experience that can make the learning curve a little less steep.
You definitely can make large items with the passthrough slot and even without it.
As Jules said, there are some basic concepts to get down before you can make things efficiently and effectively. I understand your thing that the size limitations were minimal. I was thinking 1/2 cutting made easy. It’s possible and not too hard, but it does take some learning of the alignment work arounds.
Ask questions on the forum and play around with design software. Your purchase will pay off in some great stuff.