Isn't this even more of a monopoly utility?

In theory you could have multiple providers but it just doesn't happen much due to market dynamics and incentives.

In this case if I understood it well there's a limit to the amount of satellites we can send into space at those heights and that space is essentially privatized for free uncontested and ESA and China's CNSA already complained about near collision events.

So not only do you get the same market dynamics but practical limitations too and an externalization of costs.