Try it on your wall.
Take a photo of your wall, even a bare one. Show me one thing I can measure, like a door, and tell me what will sit under the print, even if it is not there yet. Then I will hang the print at true scale. All of it happens in your browser, and your photo goes nowhere.
Start with a photo
For the best result, stand back and shoot straight on, so the whole wall (and the sofa, if it is already there) is in the frame. A photo taken from an angle will make the scale less accurate. On a computer, "Take a photo" opens a file picker.
Now put something on it
Use your own photograph
Drop in any photo to see it in the frame, and see whether it holds up at this size.
AI artwork not built yet
Describe it and I make it. This needs decisions that are not made: what it costs, what is not allowed, and how to get an image sharp enough for a big canvas. Until then, use your own photograph.