Lumen and Verizon both have subsea cable connections to Europe. EXA Infrastructure is in the process of acquiring Aqua Comms, both of which own subsea cables. Google, MS, and Meta have all invested in subsea infrastructure to varying degrees as well. These are not monopolies in the classic sense of the word but they’re not exactly owned by benevolent interests either.

That said, the point is that a malicious government with sufficient pull, for example the current Trump administration, wouldn’t have to bully very many people to severely limit the flow of information between North America and Europe. So much of the internet depends on US infrastructure that this wouldn’t be terribly far off from censoring the entire internet. In that scenario there isn’t much that can be done about it. Europe can control their own information flow to Asia and Africa but at minimum this would be a severe disruption for a significant amount of time. Other entities might take such an opportunity to impose their own restrictions and make the situation even worse.