It's no wonder that you adapted rapidly and easily to the "lower" height of the keyboard. Upward-angled keyboards are an idiotic carryover from mechanical typewriters that had to have such angulation because the keystroke travel of those machines could be up to an inch; a flat keyboard could not work. But that upward angulation is literally anti-ergonomic, the direct opposite of what is best for your wrists and hands. If you look at the most advanced ergonomic keyboards, even those by Microsoft, you'll see that the wrists are actually at the highest part of the device with the keys below the wrist so that the wrist can be held in its rightful ergonomic position -- slightly flexed downward.
In truth, there is no such thing as a keyboard that is "not high enough." The flatter the better for your health. That you transitioned quickly to the lower keyboard should be enough to convince you of that.