Early Game Can buy Healing Rite into Healing Nova first if you are out poked in lane.
Mid Game Compress Cooldown allows you to use your heal more. Rescue beam can save your team in sticky situations. Healing Tempo will allow your team to put out even more damage. Heroic Aura provides a bullet resist aura as well as give your teammates firerate.
Late Game Plated Armor and Inhbitor for your last two flex slots. If you dont have the flex slots you can sell Healing Nova and/or Cultist Sacrifice for Scourge and/or Divine Barrier. Otherwise you can upgrade Expansion and Duration.