That is not only a beautiful wonderful thing, I simply can't recall anyone, anywhere on this forum who has designed an Indy Car glider! It is absolutely Wonderful!
"It’s fun to throw but it doesn’t glide well. It just floats for a bit until it stalls and lands on all 4 wheels"
That means it's well balanced and well built. Might I suggest a little weight to the nose, to make it float less. Then maybe... I'm really guessing here. If all the vertical surfaces were not so vertical, maybe if some were angled out a bit, they'd act as lifting surfaces. Like wings.
Regardless of my input, that is a glorious build! Absolute congratulations.