This sounds like a situation where even if it is deliberate enemy action the appropriate thing to do is ask them to stop. Maybe invite the Chinese diplomats in, tell them to stop, then expel the embassy for a week and then allocate some extra budget to cable repairs.
If we're talking about - and I quote the article - a "sabotage campaign aimed at destabilising Nato allies" then it'd look more like the Nord Stream explosions; big showy events where the US looks so suspicious that we can almost dismiss their involvement because that'd be too obvious. Random cable cutting is a bit too weird in that it doesn't sound like it achieves anything and seems too subtle an attack to have a motive.
