NATO's eastward expansion, constantly compressed Russia's traditional sphere of influence, how will Russia respond?

NATO's eastward expansion is in fact to test Russia's strategic red line, although in recent years Russia's sphere of influence has been continuously compressed, but obviously did not reach Russia's strategic red line, once beyond the red line results in military conflict. And NATO is not endless eastward expansion, it is to maximize the strategic advantage over Russia, if the situation is tense or the outbreak of military conflict, then this international political and military "game" is very uninteresting, and there is no benefit to both sides. Russia's eastward expansion of NATO is certainly not happy, but it is not capable of military pressure on NATO, because it is no longer in the wind, and now Russia can only pay lip service to the nuclear missiles targeting which pro-US countries in Eastern Europe, because of the Russian army's equipment is old and military disorganization. But Russia has also firmly given NATO a warning on some serious security issues, and that was the war in Georgia that took place last year. Obviously this was a stern warning from Russia to NATO and some of the pro-US Eastern European countries, which were on the verge of exceeding my strategic red line. After all, Russia still has the last trump card, is the energy card, Russia is Europe's main supplier of natural gas, it can be used to pressure Europe, the beginning of the year, Russia and Ukraine's natural gas dispute is already a good example. But I personally feel that Russia's current task should still be the development of the economy, and countries to establish good diplomatic relations to strengthen international cooperation, as long as the future money to engage in anything.