Problem you'll run into even with 600, is that on any type of bump, even small, all the force from the weight of the bike and carrier (which is now magnitudes higher, physics and shit) will all be put on the few bolts that hold that hitch together. It will surpass the tongue weight no doubt.
A properly weighted trailer takes all that stress and distributes it, mostly to the wheels 👍
Cars and bikes are big investments, ain't worth breaking both!