On fabric, there is no in-game option or JSON file to edit the settings. I want to enable full view always.

Sorry for the late reply,
On Fabric, you'll have to install Mod Menu to get access to the configuration menu.
For both platforms, you click on Main Menu > Mods > ShulkerBoxTooltip > "open config" / gear icon

If you want to edit the JSON file manually, it is located under .minecraft/config/shulkerboxtooltip.json5.