Therefore, it might be worth it for Russia to lose a few tankers in order to keep one of their greatest assets.

All hypothetical of course. I'm sure Trump isn't a Russian asset. No way they can have kompromat on such a virtuous guy.

It’s not even clear whether they were actually Russian or if they were just flying the Russian flag to try and not get captured.

But even if they were Russian, it was a clear area in which Putin overstepped his boundary.

As in 1984, visible geopolitical conflict with a sufficient perceived degree of real kinetic threat between the empires serves the rulers of each empire by providing the external threat to maintain the apparent need for strong internal control, it also facilitates the transition from the current international status quo to the desired end state by providing a set of threats intended to coerce lesser powers to accede to the dominion of their respective regional overlords.

Regardless, without Kaliningrad being a factor, it is still Denmark's responsibility to control those waterways to deny Russia access to the North Atlantic. Having to reinforce Greenland is taking resources away from Denmark enforcing its area in the Baltic Sea.

There is a lot of information about it over the past few years from more international sources. And no, it's not imagined.

The really debatable issue is with the reported attempted agreement by the Trump admin and attempts by Russia to sort of trade Ukraine to Russia for Venezuela. If this turns out to be true, and you can find domestic reporting on this offer having been made a few years ago, then places like Kaliningrad, Estonia and other former Soviet Republics become the next targets.