LEO is going to be split between SpaceX, OneWeb and whatever China goes with. Amazon, again my opinion, I believe are late to the game.
Yes, and the suggested "EU LEO constellation" will be stillborn. I suspect they'll have to swallow their pride, suppress their Brexit gag reflex and invest in OneWeb.I don't think there will be any room in the market for Amazon Kuiper since Starlink & OneWeb already seem to be well established, and both will be fully operational before Kuiper launches a single satellite. I assume China will do something because of national pride and their need for a 'properly controlled' system, and that Russia probably can't afford to build out their own - they might go in with the Chinese, I guess.
Over two years ago, an MIT research group ran a simulation of the low-Earth orbit broadband constellations of OneWeb, SpaceX, and Telesat, and last January they repeated the simulation updating with revised constellation characteristics and adding Amazon's Project Kuiper.They ran the new simulation twice, once using the planned initial deployments of each constellation and a second time using the configuration shown below, which shows final deployments assuming that change requests pending in January would be approved. (SpaceX's have been approved). I will discuss the second simulation here, and you can consult the paper for the results of the initial deployment simulation.