Need help getting 190Vpp to signal readable by AD/DA
Given it appears that you are interested in frequency, you could probably do the signal conditioning fairly simply.

One option is a small transformer connected to the output of the sensor which provides a 100:1 turn ratio or something similar - that would give you a 1.9Vpp signal nominally that is isolated from the high voltage.

Another option would be capacitive coupling followed by a 100:1 potential divider of two resistors. Again the capacitive coupling (both + and - sides) gives you isolation as long as you use sufficiently high voltage rated caps, and the potential divider brings the signal down to something useful in terms of voltage level.

In both cases you could use a Schmitt trigger or as a zero-crossing detector circuit as @Trever points out after the division to perform a final conditioning step - take whatever weird waveform you get out of the circuit and convert it to a digital logic signal which is then much easier to process.

Once you have a digital signal with sensible voltage level you can feed that into a frequency measuring circuit. I wouldn't do frequency to voltage as you are taking a nice digital signal, converting it into an analogue signal (introducing error in the process), only to then convert it back to digital again. Instead I would use something like a simple MCU with a timer to count the period between transitions. If you get an MCU with a hardware SPI or I2C slave you can connect it quite easily with the Pi and have it report back the frequency.