Even if Starship gets into service it is unknown if it will be economically viable.
SpaceX can even launch large LEO constellations like Starlink with regular Falcon 9 launches.
I am rather skeptical about Blue Origin. It was founded before SpaceX with a lot more cash put into it.
It is after all owned by the world's richest man (Jeff Bezos). But the results Blue Origin has attained are rather miserable vs SpaceX.
The Armstrong rocket requires huge composite structures with the current design. These are cured within an autoclave.
Not only is that expensive like heck, there is a poor track record of using composites with deeply cryogenic fuels.
Of the two designs I think Starship has a lot more potential for getting put into service even if it isn't economical.
Given the commonality of the "921" rocket with existing Chinese rockets I think it will be "quickly" put into service.
Although speed isn't exactly the name of the game with the Chinese space program. So it may take 5 years.
I don't think it will be an issue if, say, China only gets their equivalent rocket a decade after Starship comes out.
In the timescales we are talking about for space exploration it doesn't make that much of a difference.
Also being a follower allows to avoid expensive forays into avenues which don't make through into practice.
Just consider that the typical Mars launch window occurs every 2 years. That's when Mars is closest to Earth.
Any Mars mission will be planned around that. So there will be a flurry of activity in those launch windows and no activity in between.
Moon mission profiles are a lot easier in comparison.