Why is my dishwasher tripping my rcd

Hi,

Pressing all the buttons at once is not a usual way to start a dishwasher. This may be setting up a condition where it will trip the RCD. Having every option "selected" (as it appears to be to me from your video) may be overloading the RCD.

I think where to start is why it doesn't start normally and go from there.

A schematic circuit of the dishwasher, (you don't state the model number) would be required to track down where the actual problem is. If you are lucky the service manual is sometimes located behind the kick plate.

Is the dishwasher still covered by the manufacturer's warranty at all?

If so I suggest that you consult the warranty statement, (usually found in the User Guide), as to what you have to do to make a claim for a manufacturer's warranty repair, replacement or refund.