PXR_SDKSettingEditor.cs in included "PICO Unity Integration SDK v211" package :

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[InitializeOnLoad]
public class PXR_SDKQualitySetting
{
[InitializeOnLoadMethod]
static void UnitySDKQualitySettings()
{
PlayerSettings.defaultInterfaceOrientation = UIOrientation.LandscapeLeft;

SetAntiAliasingLevel(4);
}

static void SetAntiAliasingLevel(int level)
{
int currentLevel = QualitySettings.GetQualityLevel();
for (int i = currentLevel; i >= 1; i--)
{
QualitySettings.DecreaseLevel(true);
QualitySettings.antiAliasing = level;
}
QualitySettings.SetQualityLevel(currentLevel, true);
for (int i = currentLevel; i < 10; i++)
{
QualitySettings.IncreaseLevel(true);
QualitySettings.antiAliasing = level;
}
// FIX : QualitySettings.SetQualityLevel(currentLevel, true);
}

}
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This code is executed on project load and domain reload (script recompilation), and iterates back & forth on the quality levels to force the anti-aliasing value, but does not reset to the initial quality level, remaining on the last one of the list, which is "Quest" in this project.

Adding "QualitySettings.SetQualityLevel(currentLevel, true);" after line 663 (see comment in above code) will restore the initial quality level.