does not plan a constellation of multiple thousands
"at least Brit-based OneWeb does not plan a constellation of multiple thousands of spacecraft"-- and then "grow to 1,980 satellites in later phases", which sounds like multiple thousands to me. No doubt if they are successful they will add more. They are higher, so harder to see for the naked human eye, but I believe that doesn't make much difference to telescopes. They will also not naturally de-orbit in reasonable time if they malfunction.
That said, I am becoming a bit of a fan of OneWeb. They are like Blue Origin in that the cool stuff they do tends to be eclipsed by the even cooler stuff SpaceX does. Unlike Blue Origin, they have working hardware in orbit. They can provide service over the oceans and poles without inter-satellite links, so they may get to the marine and airline markets first.