Viper will set sample rate to 48k and you can't do anything.
QuadDAC can handle 384kHz, but only in few scenarios. Only Direct_pcm (which can be turned on via UAPP or "HiFi" files) and DoP (DSD over PCM), but DoP handles 176400Hz and 352800Hz and 32 bit.
Most of scenarios you are able to get up to 192kHz.
Viper will route any direct or offload stream into deep buffer mixer. Deep buffer handles 16 bit and only 48kHz samplerate (unless you will change it in 2 or 3 files).
Oh and one and the most important thing. Stock Pie ROM have troubles with loading magisk modules. I mean it's working fine, but every audio file is loaded as stock. You must kill audioserver (every reboot) to reload it and it will work.
Back to stock? No problemo. LG up + proper KDZ file and you are stock.
Here is tutorial.
https://forum.xda-developers.com/lg-g7-thinq/development/rom-how-to-install-pie-stock-treble-aosp-t3914079