photography of buildings is a very specialised area of photography with its own very demanding OCD requirements, particularly with respect the the need for perfectly straight and level lines
Camera gear
this type of photography generally has a very strict emphasis on straight lines and lines parallel to the image frame, so for this to work well for you, you generally need:
this should be perfectly corrected optically with barrel or pin-cushion distortion
a geared tripod head to make fine adjustments to the angles to ensure your camera is perfectly level
eg. Manfrotto 410 Junior Geared Head
if you are shooting interiors, you often need to back your camera up against a wall or corner to get the shot
a camera with a swivel out, rotating rear LCD screen becomes your life saver for composing these images and negates the need to get behind the camera
even better if you can remotely control the camera and see the composition etc remotely on your smartphone as with most modern digitals - this allows you to be out of the frame in these tight corners without having to resort to the self-timer
a high resolution camera with excellent dynamic range helps for those high contrast scenes
Olympus OM-D E-M1 mark II can use Olympus Hi Resolution mode and has a swivel rear screen but dynamic range is not quite as good as a Sony full frame, and the 2x crop factor means there are no super wide angle tilt-shift lenses available as yet (adapting the Canon TS-E 17mm f/4L tilt shift lens gives you 34mm FOV), but you can do in-camera, live keystone corrections so you can better compose your images in-camera
remotely fired strobes
especially for interior work and potentially for those typical flattering, aesthetic, blue hour real estate shots