Well, if the bed is warped, there’s nothing you can do to print it straight, unless you printed a raft, or something, but I have other problems with rafts. But really, we are talking about 0.3mm over the span of 200mm. I don’t mind that it’s off a little, I just want a good first layer.
There’s also an option, which I didn’t read the details about, that would squish the first few layers to get them even with the bed, but by the end, the layers would be “flat”. I’m not sure how that would work. By the time it flattens out, I would hope it’s just moving along the normal of the plane, and not printing parallelograms.