Russia is clearly the aggressor here.

First, let's establish some context here. What Russia is rightly concerned about is the fact that NATO has been relentlessly expanding to the east. They've now given NATO an ultimatum that it has to roll back and comply with the original security guarantees that were given after USSR dissolved. The threat to Russia is real and should not be understated. NATO being able to put nukes in Ukraine would mean that they could reach Moscow in five minutes. This is a red line for Russia. All the NATO members have already stated that there is no prospects of Ukraine joining NATO or EU in the foreseeable future. This precludes any reason for Russia to act.

Russia has also never once said that it plans to invade Ukraine. The troops you're talking about are stationed in their barracks. Likewise, France, Germany, and even Ukraine are saying that there is no Russian invasion happening.

So far, the only countries insisting that there is some imminent invasion are US and UK. And the country that's been most damaged by these claims is Ukraine since all the investors are now pulling out leading to the economy crashing. This is the primary reason Ukrainian government has now broken with the US narrative.

Russia is achieving its goals without any need to invade Ukraine. Europe has absolutely no interest in having a full out war in Ukraine, and it's also heavily dependent on Russian gas and oil meaning that EU has little appetite to try and sanction Russia. On the other hand, US appears to be pushing for conflict as a distraction from the disastrous domestic policy and because accepting Russian demands would be seen as weakness. This is already driving a serious wedge within NATO. Russia will continue to apply pressure by doing military exercises within its borders, and negotiating with western powers. France, Italy, and Germany are already having direct talks with Russia and this is the most likely path towards resolving the issue.

Russia invading Ukraine would be counter to their goals as it would actually help unite NATO against them. There is no conceivable benefit to Russia from fighting a war in Ukraine. It's also worth noting that Russian media hasn't talked about any war, and typically countries prepare their public for a war when they're planning on having one.

The only scenario Russia has stated that it would engage militarily in Ukraine would be if Ukraine invaded Donbas. Ukraine has been ignoring its Minsk agreement commitments failing to grant autonomy to Donetsk and Luhansk, and has been engaging in committing war crimes in these regions by attacking water supply and civilian targets.