Well, that is very weird. As I say on android 9 onwards to android 12 I had 2button nav on pixel 3aXL. And this is the same for pixel 6 from android 12 to 13 stable. Maybe your device is different oneHmm, that's interesting. I thought Google removed that option from the Pixel 4 onward to push people to use gesture navigation. The only modules I have installed besides LSPosed and AOSP Mods are a blob emoji module and Magisk's own systemless hosts module, so I don't think I have anything installed that would conflict with the two-button navigation. Either way, I'm hoping that navigation system will be added for Android 13 eventually, because I like using it.