PhotoRealistic Architectural Visualization for Game/App

This is an early stage inquiry for an app/ website i would like to develop. The app is multi faceted but one element would require photo realistic room design, this area is completely out of my comfort zone so please let me know if you require any additional information.

I require someone who is able to create as close to photo realistic architectural visuals as possible. To start with we would be looking at approx. 20 one room scenes (bedrooms with walk in wardrobes, office space and retail spaces) but the requirement would be in place to dramatically increase both the number of scenes and also the number of rooms within each scene.

We need each image to be designed so that the player/user can change items within the scene while maintaining the photo realistic element, ie shadows, and reflections alter within the image depending on the item that has been changed. Foe exmaple user could change chair, wallpaper, floor etc to personise the space.

I found the below videos on You-Tube so believe its possible but need to get an idea of how complicated this is, which is going to have an impact to the viability of the project.

I would be grateful for any advice, examples that anyone is offer.

Best wishes

it was working smooth on my iPad Pro when it was running on ios 10 however as I have updated to ios 11.3 whenever now I am opening the app it only loads a blank screen on the start up and crashes after a while automatically. How do I fix it?