They will not work and are likely to screw up some things. So don't flash it on anything except a OnePlus One. Also, it's not just one or two values to be modified. I'll have to look into the name scheme of OxygenOS (how they named various audio sources and all), and then try it. I cannot make it for the OnePlus 3T because I simply don't have the device. Hope you understand.
You can use a survival script by inserting the mixer-paths.xml path.
Download this zip and extract 91-mysettings.sh file (I have already configured it)
Put this file in system/addon.d and your mixer_paths.xml will survive during rom's update.
With this script you can save other files from your system or remove some apk/files from new update during every rom's update.
For example....from new update i don't want some apks from system then i can write relative path into the survival script like so and during the flash they don't will be installed.