[OnePlus 10 Pro] zgfg:
Following up, please have again all audio modules uninstlled, reboot and then follow:

- Install the official V4A FX module

- Reboot

- Run V4A app, it will complain that there is no driver installed and it will attempt to install

REBOOT but THEN DO NOT RUN V4A app yet!

1) Instead:

- go to /data/adb/modules/ViPER4AndroidFX/system/vendor

- there must be a subfolder etc with audio_effects.xml and audio_effects.conf

- check are those xml and conf files 'patched' by V4A as on my attached screenshots (they should be)?

2) Create the following system of folders:

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc (that one must have been existed)

/data/adb/modules/ViPER4AndroidFX/system/vendor/odm/etc

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc/audio/sku_cape

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc/audio/sku_diwali

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc/audio/sku_taro

Copy that patched audio_effects.xml from:

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc

to the newly created folders:

/data/adb/modules/ViPER4AndroidFX/system/vendor/odm/etc

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc/audio/sku_cape

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc/audio/sku_diwali

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc/audio/sku_taro

Copy also that patched audio_effects.conf from:

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc

for the beginning only to:

/data/adb/modules/ViPER4AndroidFX/system/vendor/odm/etc

Copy also the attached post-fs-data.sh to /data/adb/modules/ViPER4AndroidFX

3) Then reboot, again DO NOT RUN V4A app but first check:

- do you still have the created folders and files from (1) and (2) in /data/adb/modules/ViPER4AndroidFX/system/vendor/...

Also, now in the 'real' folders, starting from root / (no more in /data/adb/modules...):

/vendor/etc

/vendor/odm/etc

/vendor/etc/audio/sku_cape

/vendor/etc/audio/sku_diwali

/vendor/etc/audio/sku_taro

- check if every of them now contains your patched audio_effects.xml from (1).

- and check if the first two contain the patched audio_effects.conf also from (1).

(they are actually not copied there but Magisk must have mounted them from /data/adb/modules/ViPER4AndroidFX/system/vendor/...)

Pls check and confirm.

Then open V4a app and if it does no more complain, switch to Legacy mode and enjoy

4) If V4a app does not pass yet but still complains that driver is missing, it will delete everything that you did in (2).

Hence reboot, redo step (2) again but this time copy both the patched audio_effects.xml and audio_effects.conf from:

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc

to all those folders:

/data/adb/modules/ViPER4AndroidFX/system/vendor/odm/etc

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc/audio/sku_cape

/data/adb/modules/ViPER4AndroidFX/system/vendor/etc/audio/sku_diwali

Reboot, again do not run yet V4A app but check if all the 'real' folders (starting from root /) contain the patched audio_effects.xml and audio_effects.conf:

/vendor/etc

/vendor/odm/etc

/vendor/etc/audio/sku_cape

/vendor/etc/audio/sku_diwali

/vendor/etc/audio/sku_taro

Pls check/confirm.

Now try again V4A app (with Legacy mode)...

Not sure would V4A app now really work but that was based on what you previously confirmed about your folders, trying to adapt how V4A mounts the patched xml and conf files to your case