The endgame here is to build a new world order with Russia and China calling the shots (actually, China calling the shots, but we're not supposed to say that yet).
Not even replying to the claims about world domination, I don't have time for these... "suppositions".
Russia is desperately trying to make the China-Russia thing a reality, and is probably trying to drag them in against their great resistance. China has zero credible reason to be dragged into Russia's nonsense, and a billion reasons why they want nothing to do with it.
The ideal outcome of this is that China realizes that Russia is outright trying to drag them into conflict, and that they repudiate that country entirely.
The Russians could have done this with a fishing trawler (they cut cables accidentally all the time), so like you I doubt we can infer some nefarious Chinese plot from the flag on the vessel.
Poland has been warning about Russia at least for over 14 years now, since before Crimea annexation for sure. It started with Russia invading Georgia, I think.
Likewise, Poland has also been meeting NATO spending quota for years, upping it even more these days.
Poland refused to let another gas pipe from Russia through its territory without it going through Ukraine too, because it was obvious Russia would use it as leverage against Ukraine. This is what actually led to NS project which, for the same reason and this time additionaly because of the risk of creating leverage against other CEE countries, Poland refused to participate in and had been instead alarming that NS will result in troubles with Russia and security of Europe and Ukraine in particular.
Poland has been raising the issue of not only Ukrainian, but Georgian situation too. Many people forget, that Russia has been occupying parts of Georgia for over 16 years now.
Poland, despite paying penalties for that and being called racist etc., has been also blocking illegal immigration influx on its border with Belarus due to it being a hybrid war of Russia against Europe.
If anything, Poland did not sleep over Russia's plans. Quite the opposite, actually.