Building an Augmented Reality space for WebAR and App

We have a requirement to build a 3D space which will be accessible via webAR and through an iOS app.

We would ideally like to build the space in Unity.

We are looking for someone who can
1. Build a 3D space in Unity (ideally) and deploy to a cost effective web platform of choice.
2. Come up with the design and modeling based on design prompts
3. Suggest optimization and best performance practices for this 3D space.