Hi
You can resitor devider to reduce voltage before measure, but safety for measurement tool is very importance. We can't lost osciloscope for this.
Because of high voltage, so resistor need serial to reduce voltage drop on each. Resitor value also too high (xx Mega ohm), will using probe it has 10M (not fix) ohm 6pF (not fix) impedance, this can act as low pass filter, and the wave form read on Osc is not real. -> need a pre-amplifier to recover signal and buffer for Osc.
You can take alook in LISN use to measure EMC.
Or use can use wireless module with ADC > 5 x 25kHz (100khz) sample rate, using pre-amp filter only measure ac-voltage, then log data to RAM, then send BLE, Wifi to host. Isolation space up to few meters. -> Don't need worry about leakage current.