Ahem... Cui prodest/cui bono?

What kind of interest Chinese could have to damage such cables? IMVHO ZERO. Also I doubt Russians have interests to do so.

Who could be interested?

- some private company for makes and insurance/the public pay to fix something who need money from the owner for other reasons (like I break on purpose my car to get it repaired for free or at least less money than what it would costing me avoiding the self-sabotage);

- some countries wanting war at all costs trying to create a casus belli to justify the push toward WWIII

- some countries experimenting the resilience of their infra

I fails to see any other potentially interested party.