How to reduce/remove piezo pickup hiss
Having read extensively the posts on 'diyAudio.com' about the challenges of achieving low-noise performance with JFETS for RIAA vinyl record playback with MovingCoil phonocartridges, one noise source is hot-carrier currents needing an exit path out the gate. Your exit path is 3.3MegOhms.

Experiment with reducing the Rgate.

Regarding the "super loud", you can reduce the gain by reducing the 1.5Kohm to 560 ohm or 220 ohm. At 220 ohm, your gain is actually 'attenuation', of 10 dB.

The 'diyAudio' NJFET is 2SK170, usually cascaded with bipolar to hold the drain stress to 20 volts or less, for purpose of avoiding hot-carrier-gate-current noise. In this circuit, the J113 exhibits that noise with only 9 volts.