Why would Russia want to blow up NATO-controlled pipelines? What are the incentives for Russia to do so?

Zugzwang: If Europe can't replace Russian gas with Norwegian gas, then Russia has not only some, but all the leverage over Western Europe. This puts political actors in Europe into a position where they have to react quickly without really knowing what is going on.

Why would NATO want to blow up German-controlled pipelines, instead of just exposing "Russian plot" to destroy Baltic pipeline?

Contrary to common believe, Western elites might be less or not yet interested in a full escalation of the war against Russia. It's better to keep it burning in Ukraine. The more troops and material Russia loses there, the smaller are the expected casualties for NATO.

If Nord Stream blows up, who gains the most? Is it Europe which is already in energy crisis, or the US which recently became the top LNG exporter of the world and selling LNG to Europe for big profit?

There are two big points that I see. In the short term, Russia would send a clear and terrifying message to NATO/EU countries: We can blow up your entire infrastructure in open waters, which would completely cripple Western Europe and set it back 50 years.

In the long run, the explosions will cause a massive increase in costs for maintaining infrastructure in open waters. Pandora's box is open in this regard now, everyone will have to adapt for this risk element. In consequence, land connections will become much cheaper in relative terms - and what country has the biggest landmass and most neighbor countries again?

or the US which recently became the top LNG exporter of the world and selling LNG to Europe for big profit?

If Europe shuts down even just temporarily for a couple of days, then it will take decades to build up the current economic potential again. Europe and especially Germany are currently de-industrialized by its own elites. They certainly have no interest in rebuilding the systems again.

Two thirds of energy demand in Germany is industrial. If that is gone together with the wealth that Germany's industry created, then nobody will need American or any LNG anymore. George Gammon had an interview some time ago I can recommend on this topic. It's mainly about the BASF Ludwigshafen chemical compound, but that's just the biggest site, there are many more in the same andother industries, for which things look similar. (Fun fact: BASF is one of the main Russian gas shareholders on the German side.)

Beyond that, in case a bigger blackout should happen, then a serious depopulation might follow right after. At the moment, Germany has some 84 million inhabitants. Among them are around 10 million opportunistic migrants, who will leave quickly again as soon as the cow providing them with milk is dead. On top come 13 million 70+ year olds of whom most wouldn't survive the next two years, or even two months after a blackout.

By 2024, Germany will likely have ~30% less population and ~75% less industry. As a result, the overall energy demand will drop to 40% of today's demand. Now check out the below cake chart on the right. Yellow is renewable (=domestic) and grey is conventional (= mostly imported).

Do you get it now?

Germany's current elites don't mind that this is happening. In fact, they are open about it and work towards this outcome. Watch this 25 minutes long episode of an old W-German scifi show. It will show you what their thinking is, how they conduct themselves and what they have in mind with us. The young eco-leftwing recruits of the 1970s who were put into this mindset are in charge of the country now.

Bottom line: If the United States did the bombing of NS1+2, they certainly didn't do it, because they want to become the monopolist seller, but because they have the same mentality. In case though, they did do it with selling expensive LNG to Germany in mind, then it's time for them to get a new intel department.

sry for tldr;