Excessive engine oil consumption but no smoke. Leak seems near propeller shafts leading to wheels.
You won’t necessarily see smoke due to the catalytic converter, not that burning oil is good for it. How much is “excessive”? How bad is the leak?
That would be a transmission leak. Different oil, different problem.
Engines can consume a lot of oil past the piston rings without much visible smoke. The spark plugs would be black and sooty at the tips.