Well there is if you go far enough. It's just the question when did they split off from each other. However there is no question that Baltic and Slavic are more closely related to each other than any other non extinct Indo-European languages.
The fact they they are the closest surviving relatives on it own doesn't mean it makes sense to group them together (i.e. Italo-Celtic is also a theorized subgroup in a similar way but nobody is disputing that Celtic and Italic languages evolved into distinct groups).
Then there is a huge amount of missing links and unknown unknowns. e.g. Thracian and Dacian probably were also pretty close to Baltic or Slavic (maybe even closer to Baltic than Slavic is but we don't know enough about them to make any conclusive claims at all... but we at least know these languages existed)
Plenty of wrong here, considering Lithuanian and Latvian are utterly unintelligible to slavs, save for loanwords, but Slavic languages between themselves retain some level of intelligibility, which even spawned two competing constructed languages.
Yup, most of Eastern Europe are Balto-Slavic. While the division from the Eastern Slavic languages (Russian, Belarussian, Ukranian, etc) is distant, they are still Slavic. From Eastern Europe, only Estonian is not a Slavic language.
I regret being that loose with the designation :), Romanian and Hungarian are valid counter arguments.
In my mind, I was thinking of the belt of countries between Russia and Central Europe, starting from the Baltics down to the Balkan (excluding Greece).
Even by your definition, I can count at least seven countries where the official language is not Slavic. And that's not even including all the Altaic, Romance and other assortment of regional languages, many of which have some sort of official status.
Some of my fellow Romanians will also claim they're Central European, but in my mind, all the ones I listed are Eastern European countries. I'd even include Turkey and Kazakhstan in there, part of the latter is to the West of the Urals, which is what we normally consider the border between Europe and Asia.
That's cute. It is clear thats an outdated political organization and not geographical. Read at the groupings. Greece is more eastern than Albania (and it is one hour off timezone), and it says 'western' which is not the case by any geographic means.
“There’s a question” implies that there is a ground truth that might be discovered to resolve this rather than simply a clash of different purely arbitrary definitions of the same terms.
Ah, yes, how could I forget! As a side note, though also Finno-Ugric then similarity in sound and appearance from Finnish or Estonian at least appears very far.
The Visegrad 4 (Poland, Czechia, Slovakia, Hungary)are generally taken to be "Central European". The strict East/West division is largely a product of the Cold War and the Iron Curtain.