Big Sienna Hybrid Factory Tow Hitch problem

Anyone had this problem with their 4th gen Sienna?
In 2021 I ordered a Sienna XLE AWD with factory tow package from Concord Toyota in California. We waited 5 months and finally received it in May 2021.
In all of the Sienna specifications the tow rating of this vehicle is stated to be 3,500 lbs when equipped with a factory tow hitch.
Now that we are looking to tow a camper, the trailer dealer tells us that our hitch is only rated for up to 1,500 lbs. The factory hitch is a 1 1/4" receiver and cannot handle more than 1,500lbs.
When we ordered the Sienna and optioned for the tow package, there was no information stating that the tow package would only allow for up to 1,500 lbs.
The dealer sales man also did not say anything about a reduced tow rating.
All marketing materials detailed 3,500 lb tow rating with the factory hitch.
I have now mentioned this to our Toyota dealer, the service department and also called Toyota customer service. Everyone has said 'Sorry, but we cannot help you with this issue.'

Has anyone else had this issue? I can't imagine that I'm the only new Sienna owner out there with this experience.
I also can't imagine that Toyota would sell a van and hitch combination like this with no warning to the customer, while promoting that this combination will actually work to tow 3,500lbs.

I feel like Toyota is dismissing this issue and deciding to take zero responsibility. This is actually a large mistake and there really is no easy solution as the hitch will need to be cut off of the frame.

Hoping someone has some advice for us - or at least get the word out about the new Sienna's issue with towing.

I have to say - the van itself is fantastic. 5 star vehicle. This towing issue is a big bummer though.