The physical and pixel size of the image are deliberately explicit to give you control over the image that will be returned. This is further complicated by the fact that True Ortho and DSM are of different native resolutions (0.055 m versus 0.15 m).
Request the imagery by inspecting the coverage response and then calculating the pixel size based on the metadata.
If, for example, you want an image of 100m radius. The total width or height is 200m.
DSM image size is 200 m / 0.15 m/px = 1333 px
True Ortho Image size is 200 m / 0.055 m/px = 3636 px
You can then request content types at their maximum resolution or, for example, upscale the DSM to match the True Ortho image pixel by pixel.