It may depend on local laws. Here the total weight of the combination (car + trailer) with a B+E driving license is 7000Kg, and 3500Kg for a car. That means you can have a van with 3500Kg capacity plus a 3500Kg trailer. So naturally there are vans that are built to match the max spec.

most vans are limited to around 750 kg, whereas trucks typically offer much more. Mine can tow up to 3000 kg.

Yeah that’s bullshit. Vans that can do the max of 3500kg are common as fuck. You probably looked at the wrong spec. 750kg is the max for a trailer without brakes, regardless of type of car. There are usually two numbers on the spec sheet, one for max towing weight for unbraked trailers and one for braked trailers.