Car trailers are around 700kg ish empty.

That braked towing weight just means you can tow a ton without ripping the brake discs apart every time you brake. Any more and you're beyond the design weight of the vehicle and illegal.

With the combo, the combined total must not exceed 2815kg including you sat in it with any equipment you decide to carry.

Slightly over and they will make you remove stuff or stop you from continuing on your journey. More than 300 kg over then they will spank you.