Actually there is a Render Grid which seems as a perfect fit for my use case if I can exclude it from exports. I was trying to emulate that by adding a mesh and a grid material on it. I wanted to make it non pickable and non transformable with gizmos.
However I get errors when ı click this in my app:
Uncaught TypeError: Cannot read property 'ShadersStore' of undefined
I have made a dedicated topic for it here.