TLDR: It's based on a translation error and unclear geographical terminology
Kaliningrad isn't seen by Russia as a viable area denial chokepoint vs the Baltic Sea anymore. Whatever else the paper covers - "New challenges" is plural - the paragraphs about domination are only concerned with area denial from Kaliningrad. This is a naval (Baltic Sea), not ground (Baltics), segment of the paper.
Finland is hardly mentioned in the surrounding paragraphs, except to state that Russia's air operations near it have been rather cautious lately. It gets a lot of coverage elsewhere, on other challenges.
Original paper in French New challenges for Russia in the North and Baltics
Here it is in the paper
(Page 13, bizarrely tucked into a paragraph denoting the sad travails of the 18th Guard Mot Infantry Div. note the very similar phrasing and terms - dominate/cancel+abandon):
I think it makes a lot more sense and the rather confusing arguments made around how much sense the paper made are due to a translation error.
la partie centrale de la région de la Baltique
is translated as
the central part of the Baltic region
But "la Baltique" in French is the Baltic Sea, not the Baltic countries (singular vs plural, gendered language, "la" vs "les", subtleties entirely lost when translated to "the" in English). So bearing that in mind:
Ce qui peut maintenant être affirmé avec certitude est que
l’objectif stratégique de transformer Kaliningrad en un « bastion »
lourdement armé qui pourrait dominer la partie centrale de la région de la
Baltique a effectivement été abandonné, mettant fin à des débats souvent
acrimonieux en Occident. Le succès des frappes lancées par les missiles et
les drones navals ukrainiens sur l’infrastructure militaire en Crimée a
prouvé que les forces russes ne peuvent assurer une interopérabilité efficace
entre différents systèmes d’armes de défense air-sol et côtière, qui est
nécessaire pour rendre le modèle stratégique A2/AD fonctionnel.
What can now be stated with certainty is that
the strategic goal of transforming Kaliningrad into a heavily armed "bastion" that could dominate the central region of the Baltic Sea has effectively been abandoned, putting an end to the often acrimonious debates in the West. The success of strikes by Ukrainian naval missiles and drones on the military infrastructure in Crimea has
proved that Russian forces are unable to ensure effective interoperability
between different air-to-ground and coastal defense weapon systems, which is
necessary to ensure the functionality of the A2/AD strategic model.
.. some more stuff about Baltic Fleet drawdowns to move their gear to Ukraine ...
Further down:
Overall, the garrison of "Fortress Kaliningrad" has been shrunk significantly and the ability to safeguard supply chains has been lost, but the Russian high command shows little
shows little interest in this profound strategic vulnerability.
So, basically, this is saying: from what we've seen in Ukraine it turns out that Russia can't dominate the sea (A2/AD) near Kalingrad as they struggle to coordinate their missile systems, as well as their air defense, so they would be more sitting ducks than a full area denial threat to that part of the Baltic Sea.
Note the references to "bastions" and "garrisons". This is a fortress, a defensive force, not a force to go raid the neighbors on land. But it does make sense if you want to maintain your hold on a chokepoint.
Additional points
Using Kaliningrad as choke point vs the Baltic Sea would make sense in the initial stages of a conflict before ground actions took place. Think "Houthis" in Yemen. It's a graduated escalation mechanism. Russia and NATO do not invade each other, they just take pot shots.
If you were to do this, your first priority would be to protect against NATO air/missile attacks. As Kaliningrad, IIRC, just moved some of it SAM assets to Ukraine, Russia seems to have shelved that idea entirely, for now.
The bit about coordination between surface-to-air and coastal defense is a bit confusing. But I recall War on the Rocks mentioning that Russia can't fire SAMs in an area its aircraft are operating in, unlike NATO. So, to move aircraft somewhere, they "turn off" SAM coverage for the entire zone. That would be problematic when operating coastal aviation. Mind you, that is a hard problem, as one can see from the frequent preponderance of "friendly fire" casualties in NATO operations.
The Houthis? Are still being a pest, with much less sophisticated systems than Russia's. So maybe it is a bit of "vendre la peau de l'ours" / "count your chicken before they're hatched" from these analysts.
Unlike colloquial speech, and especially so in French, "dominate"/"dominer" has a particular military meaning relating to artillery looking down and controlling an area which seems to be its usage here, rather than "being stronger" or "kicking butt".
This bit, btw, doesn't seem all that related to Finland. But it is very much what the original article says.
Translated with DeepL.com (free version)
What I originally started answering
The accession of Finland and Sweden to NATO has undermined Russia's strategic planning, in which the Baltic and Arctic theaters constituted distinct axes under different command, with specific objectives that exploited a military superiority now lost. Russia has gained unrestricted military access to Belarus, but troop shortages are hampering the effectiveness of this alliance, while the deployment of non-strategic nuclear warheads is highly problematic.
(Translated with DeepL.com (free version))
So basically they seem to be saying two things:
Russia has a lot less troops to throw at the problem, and they note Russia has taken troops out from Kaliningrad to Ukraine.
And its Arctic zone troops (Finland?) and Baltic zone troops (Baltics) now face a unified enemy command. So they can't just attack and figure everything else is calm in the area and that Finland is not going to pressure them.
That seems a factor, though Finnish army troops wouldn't necessarily be great to cross over water southwards to help the Estonians and Lithuanians. Not with that inconvenient Leningrad Naval Base nearby. But St. Petersburg itself would need protecting.
At the end of the day, no matter how you dice it, a NATO Finland is a lot less comfortable for Russia in this kind of special military operation adventure than a neutral Finland. Note however that the article is not that relaxed about Russia all the same as they note:
Indeed, Russia has lost its position of strength and ability to threaten its neighbors with projections of its military might, and while to many Western political strategists these changes seem artificial and temporary, in Moscow they are perceived as both unacceptable and irreversible.
Related: Kaliningrad: Impregnable Fortress or “Russian Alamo”? | CNA . May 2023, though, before some of K's S400 got shipped out.