>>>OP didn't say anything about Russian Navy specifically.

To discuss options for Russia's future without the specific context of its national security interests is meaningless when the country's decision-makers are almost entirely from said national security apparatus.

>>>However, do you suggest that Russian Navy couldn't use Novorossiysk for military purpose if need be?

This 2013 report suggests that Sevastopol has superior all-weather access compared to Novorossiysk: [1] I'm not familiar enough with the meteorology of the region to articulate why. They probably could switch to the Caucasian coastline as a fallback plan, but I'm sure Russia looks at the problem from the lens of "we're a nuclear-armed Great Power, why the fuck would we compromise on this?" Sevastopol definitely provides better power projection across the whole Black Sea. [2]

>>>Well, Russia is now getting additional 1,340 km border with a new NATO member (real, not imaginary one like Ukraine) and is apparently completely unfazed by it.

I think they were completely blindsided by Finland abandoning its long-standing neutrality, and have very few tools in their toolbox to leverage. While the Finnish border threatens their access to the North Sea, it poses less of a risk to Moscow than the Ukrainian border does. If you wanted to take Moscow from Finland, you need to secure the M-11 highway as an MSR....which means you have to secure St. Petersburg (good luck storming a city of 5 million+) or bypass the metro area and leave your supply line exposed. Russia is moving conventional combat power from the North, just as Russia is moving conventional combat power from everywhere into the Ukraine wood-chipper. They've also stepped up rotations of nuclear-capable strategic bombers in the north as a compromise to signal "don't try anything stupid up here, we've got nukes!" Of course the Finnish Air Force is rather large and capable, so I'm not sure how credible that threat is. Overall I now rank Putin pushing Finland & Sweden into NATO as the greatest geopolitical failure of the 21st century, dethroning the invasion of Iraq. Interestingly, Stalin made some similar blunders in the late 1940s/early 1950s against the West.[3]

>>>Really makes you think whether they were really worried about spooky-scary NATO or pursuing some other goal in Ukraine all along...

Even when Putin had Ukraine as a borderline vassal state they were bitching about NATO expansion in their near abroad. Some of these arguments were made in the US Congress before Putin even came to power. [4] In particular, skip to the comments by Jonathan Dean and Michael Mandelbaum.

>>>this is not WW2, nobody is tank-rushing capital of nuclear superpower via highways lol.

It doesn't matter what you or I think about tank rushes, what matters is what the Russians think about tank rushes. [5] In case you missed it, they initiated this invasion with a multi-axis armored blitz towards Kiev combined with an air assault to secure a nearby Aerial Point of Debarkation. The Russian military establishment has maintained that the offensive is the key aspect of warfare, and that the tank is the key component of the offensive, since the 1930s. Their current military thought leaders also place a priority on "active defense" aka preemptive elimination of threats. [6]

The qualifier "of a nuclear superpower" doesn't add much to the conversation. Of the major nuclear powers, only India has a capital closer to an adversarial border than Russia (I don't count Pakistan or Israel as "superpowers")....and India maintains an exceptionally large tank fleet, and has fought some of the largest post-WW2 tank engagements between their capital and their border with Pakistan.

>>>you seem to be awfully poorly informed about European history

Pretty sure ad hominems are against HN guidelines, but since you wanna go there...

>>> USSR _were_ part of the alliance

Oh? What "alliance" was that, specifically? As always, the devil is in the details. There were only two signatories to the Molotov-Ribbentrop Pact: the Soviet Union and Germany. The Soviets had a bilateral agreement for the partition of Eastern Europe. That made them "co-belligerents", not "allies". They never signed any treaty with the Axis at large (for example, the Pact of Steel or the Tripartite Pact). They submitted a revised proposal for joining the Tripartite Pact to Germany which was quietly ignored as preparations for Operation Barbarossa were already underway. At no point in time was the USSR allied with Italy, Romania (14 divisions, almost 10% of the invading forces), Slovakia, Finland, or Hungary. There is one thing we can agree on: the Soviets absolutely miscalculated....when they took their Western neighbor at his word that he would adhere to the Non-Aggression Pact that they had signed.[7][8][9][10] And you wonder why the Russians have no desire to repeat that mistake, when we tell them NATO isn't a threat?

TL;DR = Read more. Condescend less.

[1] https://jamestown.org/program/the-future-of-the-russian-blac...

[2] https://www.tellerreport.com/news/2022-04-27-from-sevastopol...

[3] https://www.wilsoncenter.org/sites/default/files/media/docum...

[4] https://www.govinfo.gov/content/pkg/CHRG-105shrg46832/html/C...

[5] https://turcopolier.typepad.com/sic_semper_tyrannis/2016/04/...

[6] https://community.apan.org/wg/tradoc-g2/fmso/m/fmso-monograp...

[7] https://en.wikipedia.org/wiki/Molotov%E2%80%93Ribbentrop_Pac...
[8] https://en.wikipedia.org/wiki/Co-belligerence#Germany_and_th...
[9] https://en.wikipedia.org/wiki/Tripartite_Pact#Soviet_Union
[10] https://en.wikipedia.org/wiki/Operation_Barbarossa#Order_of_...

EDIT: forgot these two additional general resources on understanding Russian national security thought:

https://en.wikipedia.org/wiki/Foundations_of_Geopolitics

https://csl.armywarcollege.edu/usacsl/publications/RUSSIAN%2...