Propellers - is that the latest greatest invention?
Props in modern propfan configuration are twice as fuel efficient as turbines. At subsonic speeds the higher the bypass ratio the more fuel.efficient the engine is at cruising speed. This is why you are ever larger success fans on the fronts of turbines gas generators. This is also why the 737 max 8 with is much larger fans is so much more fuel efficient than the prior gen 737.
Propfans have a 50+ bypass ratio and can cause at mach .8 the same speeds as ducted fans do. So yes modern sweeped propellers are cutting edge technology. The challenge has been noise the blade tips at take off go supersonic and the thousands of sonicbooms per second are extremely loud. Duct fans also go supersonic at takeoff power you can hear this same effect as that loud droning sound from the engines at takeoff that’s tapers off as you get to cruising speed and the fan slows to subsonic tip speeds. 737 max engines have a very loud takeoff drone to them due to the much larger carbon fiber fan diameter the engine duct traps a good amount of this noise but not all of it.
Look at the specs on this vs a ducted fan of equal thrust.
https://en.m.wikipedia.org/wiki/Pratt_%26_Whitney/Allison_578-DX