Resonance issues😕

On my Ratrig V3.1 500x500 (enclosed, with removed front and top panels) I get the first plots. The frequencies of the peaks are nearly the same, but the amplitude of the dominant peak is different. So when I run the input shaper compensation the central frequency is at 30 for x and around 60 for y. Is this normal? What can i do to improve here? I have tightened all screws and tied every hanging piece... Thank you!