75% of the problems raised in the question can be solved by buying or making your own shooting light box. I made mine with a cardboard storage box bordered on each side and the top with a strip of led lights covered with semi-transparent white paper to avoid glare. This is less than ten percent of the amount referred to in the question.
With that light it is enough to eliminate the separation between the floor and the wall, but if you still do not trust the result, instead of putting a Cartesian background, use one without a fold like a white PVC:
Regarding the brightness of the original photo, in addition to the ambient light provided by the light box LED, there are (at least) three spotlights, one on each side, the one on the left more powerful (or closer, nr. 2) and a top one, is deduced by the projected shadows.
About the type of photo, it can easily be done with an iPhone, but I would recommend a tripod to adjust the frame as much as possible. With a tripod, zoom, and good angle you can avoid or at least hide the perspective distortion.