I agree with all of that.
It seems that any increase in power, larger dia prop, is going to cause problems as the mast gets longer.
Somewhere about 30 odd years ago I had the quaint notion that a smaller dia ducted fan system might work.
I built an enclosed turbine motor device about 4 inches dia, ran it on compressed air at 10bar and got about 12000 revs, no load, still got it somewhere. The idea was to use a series of fans in a Venturi tube, prob about 3 feet dia 2 feet long driven by a hydraulic pump/engine. Two of those side by side driven off one decent engine placed wherever suited the CofG.
The whole idea was to get the rotor/mast down as close to CofG as possible.
I never got the chance to build anything so it remains in the daft ideas tray.
I still think the rotor drag is not being considered enough. CofG and thrust line, yes but that long mast bothers me.