Ukrainian isn’t a dialect continuum with Russian. That’s a myth commonly pushed by Russia and Russian nationalists. It’s a separate language with roots diverging from a rather early point with different history. It actually shares more similarity with Polish or Bulgarian than it does with Russian. Here’s a good video on the languages https://www.youtube.com/watch?v=CQLM62r5nLI
(Note: It was published before the war so the statistics of where what languages are commonly used have changed dramatically.)
Surzhik spoken everywhere east of Dnieper, in Kiev and and Odessa certainly is a dialect continuum with Russian. Most often it's simply Russian with a Swadesh list of 100 words replaced by their Ukrainian counterpairs, whenever possible. The rest being left as is.
Nobody really cares what these far western ukrainians are up to. Russians don't really want them. Maybe with the exception for one dude from Vinnitsa.
Eneida by Ivan Kotliarevsky [1] (1798) is first literary work published wholly in the modern Ukrainian language. Ivan Kotliarevsky lived in Poltava, East Ukraine [2].
Valuev Circular [3] (1863), Ems Ukaz [4] (1876) banned the use of the Ukrainian language in print. Religious books on Ukrainian were banned century before [5].
Census [6] (1897) maps Ukrainian language majority far beyond Ukraine current borders. Annexed by RSFSR, Russified by force. Continuum of ethnocide by Moscow.
Еней був парубок моторний
І хлопець хоть куди козак,
На лихо здався він проворний,
Завзятіший од всіх бурлак.
So you are saying this is not a dialect of Russian? Any Russian can understand 50% of this text right off bat, 80% after a day of effort and 95% after a week.
Nationalists like to draw fantasy maps. Want to see mine?
Roma, Romania, do you claim Italian is "Romanian dialect"? Muscovy was Rus colony, grew under Golden Horde, renamed in 1721. Rus Grand Prince Володимѣръ Свѧтославичъ — Ukrainian name Володимир (Volodymyr) not Moscow Владимир (Vladimir). Language of Kyiv can't be dialect of its former colonies language.
Slav languages are mutually intelligible. I've checked spoken Slovak, Polish, Croatian, Bulgarian. Do you claim these are "dialects" of Moscow language?
Eneida translated to Polish:
Eneasz rzutkim był młodzianem,
Podobnym całkiem do Kozaków,
Radzącym z każdym złem spotkanym,
Zawziętszym nawet od burłaków.
Russian (Russish) language is recent development. First song in Russian language was publicly performed by Fedor Shaliapin as demonstration that Russian language can be used instead of French language in culture: https://www.youtube.com/watch?v=aMCFALhS90c
Okay, okay, so? The point is, there's a hell of a lot of songs, books, science articles, movies, video games and other kinds of content in Russian now. It's standardized, everybody can read, speak and write it. Things are going around Russian language. It's an UN and UNESCO language. A lot of goodies.
So it makes sense that everyone who is fluent in both Ukrainian and Russian will be consuming Russian content 90% of time. Hence people no longer use Surzhik anywhere east of Kharkov (or Khabarovsk), even if some of their ancestors actually spoke it. It just don't make sense to do that anymore.
It does not help that literature Ukrainian has a lot of borrowings from Polish, Romanian and Hungarian and is not really accessible to people who did not visit Ukrainian state schools. However, Russian is very accessible to basically everybody in Ukraine and the rest of ex-USSR.
Regarding folk songs, people actually did a lot of digging in this area starting with late Soviet times, and now there's huge revival of folk music in Russia. Many contemporary pop or rock bands use Russian (Slavic, maybe even Ukrainian) folk motives in their songs, which are usually in Russian. By doing so, they enrich Russian culture, which I've started this comment from.
Ukrainian language with 1000+ years of history, is not a dialect of Russian (Russish) language, which is a very recent development, with so high number of words borrowed from Turk languages, that it makes hard for Russians to understand other Slavic languages, except Bulgarians, which are also have some Tatar origin.
Use of Russian language shrunk by 2x in last 30 years, while Ukrainian language increased by 2x in last 30 years. At some point, it will flip.
Regarding folk songs, just name one Russian folk song in Russian language, for which I will not be able to found author by 5 minutes of googling.
I'm not sure why I will be doing all that. A great Ukrainian folk song Zhuravel' was rediscovered by Chstyakov I believe, and is now fertilizing the Russian culture.
No, it's other way around. Russian (Russish) language was based on Russian Church-Slavonic language, which is based on Old South-Slavonic language. Ru with many words borrowed from Ukrainian (Russian) language.
For example, Ukraine holds word record by number of folk songs, while I was able to found none of folk songs in Russian (Russish) language after years of searching. Folk songs exists in Russia Federation, but they are not in Russian (Russish) language. Cuban Cossack Choir - folk songs are in Ukrainian language, Ural Cossack Choir - Ukrainian, for example.
You're mixing written versus spoken language. Russian people largely cannot understand any Ukrainian when spoken. Polish people on the other hand can make out bits of Ukrainian.
(Note: It was published before the war so the statistics of where what languages are commonly used have changed dramatically.)