Why if I place the zero of the lead compensator at lower frequencies, do I obtain a resonance peak?
The first compensator $\frac{3s+1}{0.1s + 1}$ has a high-frequency gain of 30.

The second compensator $\frac{6s+1}{0.1s + 1}$ has a high-frequency gain of 60.

The difference is 6.02 dB, it looks pretty close to the difference between the green and red line.