There’s no /etc/pipewire folder, and putting the configuration in ~/.config/pipewire/pipewire.conf didn’t work either.
EDIT
Nevermind, not sure if it was the file inside .config, but now when I change the sample rate from the device, it stays that way instead of reverting.
Not sure if pipewire is doing converting it down though, I’ll have to do more testing regarding latency to confirm it.
If you made changes to your user environment ie in ~/.config/pipewire/pipewire.conf you would need to log out and back in for the changes to be made effective I think.
Many software apps look in local user .config and then in /etc/appname and then /usr/share/appname in that order. This is so defaults can be overridden by the system admin or the user. Not all software does this due to security concerns. I do not know how pipewire behaves.