How can I change these Settings for pulse audio?

[Burni]

Hi,
I´m on a GPI Case with Raspery Pi Zero2 and Recalbox 9.1.
Everything runs fine except I have soundlags/cracks with pulse audio diver and vsync enabled.

Tried everything I found online but only got it a little better.
Some games run fine without vsync but some are just not enjoyable.
Alsathread audio driver works but have other problems. Wanna use pulse.

So I discovered on a few pages this fix:
I should edit /etc/pulse/default.pa
this line:
load-module module-udev-detect
change to this:
load-module module-udev-detect tsched=0

For almost every user with the same problem it was fixed.

So there comes my question:
Where is this folder and file to be found?
How can I change this line in Recalbox?

Remember: I use it on a GPI Case. I can only put the SD-Cart into my PC to make edits. But I don´t find this folder or file.
Where is the linux file strukture?

sources:
https://www.linuxquestions.org/questions/slackware-arm-108/rpi3-sarpi-retroarch-stuttering-sound-*finally*-fixed-via-pulse-audio-tsched-setting-4175671360/

https://askubuntu.com/questions/371595/for-pulseaudio-what-does-tsched-do-and-what-are-the-defaults

https://wiki.archlinux.org/title/PulseAudio/Troubleshooting