There is no need to worry about oscillation if the gain margin of the analog circuit centering on the operational amplifier is 6dB.

Plotting the Bode diagram of the negative feedback shows that the phase lags 90 degrees when the slope of the gain characteristic is 1st order (-20dB/dec), the phase lags 180 degrees when the slope is 2nd order, and when the slope becomes 3rd order, You can see that the phase lags by 270 degrees.

In order to secure the phase margin, it is important to pass 0 dB while maintaining the first-order slope of the gain characteristics in the frequency range you want to use. Then the phase margin is "ideally 90 degrees".

We would like you to think of the figure of -20dB as an "ideal value" rather than a "stable power supply condition."