Easy way to disable all panels except for the current one in Unity

Stick them in an array, iterate on the array. So on your button that opens a panel, send an index value that corresponds to the panel to be opened. Then you can just turn on that panel from the array. Something like this:

[SerializeField] GameObject[] panelList;

void ResetPanels()

{

    for(int i = 0; i < panelList.Length; i++)

    {

        if(panelList[i].activeSelf) panelList[i].SetActive(false);

    }

}

public void OpenPanel(int index)

{

    ResetPanels();

    panelList[index].SetActive(true);

}