The LOW rates default to 70% of the high rates using that TX.

Set your high rates to equal the recommended throws and you'll have a docile flyer to start with.

Later I'll bet that you'll want more throws, and will probably want to max out the ailerons and increase the movement of the elevator and rudders.

You can do this mechanically... e.g. move the linkage on the servo horn OUT and the linkage on the elevator or rudder horn IN.

Unfortunately the dx5e does not permit you to adjust servo travel...