I miss the fundamentals of the discussion.
What is your goal?
What is the max weight you want to put on it?
A monopod for me is more about holding a set up longer and giving a bit more stability, but high need of movement. Without head the latter is a pain. e.g. car races, boat trips in bird reserves, etc...
A light tripod is more about stability and selfies. e.g. long exposure, timelaps, panorama
A heavy tripod is all about stability. e.g. high resolution (D810), long telephoto (heavy), low light situations
I also looked into Sirui (Chinese make which does not want to crash prices), I`m looking into heavy, but they have some light with integrated monopod.
Last remarks: Monopod, I would go for metal (it is good enough), for tripod carbon (vibration reduction reason). Also consider a video monopod with 3 feet on the bottom, I added this to the 680B so I could use it as stand for flash.