Just how Russian is the Donbas region of Ukraine?

The other thing I have been wondering recently, in the context of the Russian invasion of Ukraine, is just HOW Russian the eastern Donbas region of Ukraine actually is. And, of course, like everything else, it's complicated.

A couple of maps from Wikipedia help. The first shows the towns, villages and districts of Ukraine with a majority of Ukrainian speakers (blue) and those with a majority of Russian speakers (red):

Donbas, including the two "separatist" regions of Donetsk and Luhansk, is the red stain in the east of the country (redder than any other region except the Crimean peninsula in the south).

Another graphic shows the percentage of native Russian speakers in the various oblasts of Ukraine:

So, 74.9% of Donetsk and 68.8% of Luhansk speak Russian as their first language. This is not, however, the same as the percentages of people claiming Russian ethnicity, which is only 39% in Luhansk and 38.2% in Donestsk (58% and 56.9% respectively claim to be of Ukrainian ethnicity). So, a good proportion of ethnic Ukrainians in the region actually claim Russian as their native language, which raises the question of exactly what "ethnicity" actually is... 

And neither does any of this answer the question of how many residents of the region would want - given a choice that they will almost certainly never get - to be part of Russia. Putin, of course, assumes that the two separatist regions would become Russian at the drop of a hat, but that is by no means clear to me. One survey concluded that around 40% (i.e. a minority) of Donbas region residents have what the survey calls a "Soviet identity". But if there was a referendum tomorrow (ha!), would the people of the area actually vote to secede from Ukraine?

And, for the record, the Donetsk People's Republic and the Luhansk People's Republic, which self-declared their independence from Ukraine after the Russian invasion of Crimea in 2014, are officially recognized by all of one member of the United Nations (er, Russia), although assorted Russian pawns and  toadies. like Venezuela, Syria, Nicaragua and Belarus, have "expressed their support". The Russian-backed separatists actually only control about a third of the Donetsk and Luhansk regions. Ukraine itself regards both breakaway "governments" as terrorist organizations, and refers to the regions as "temporarily occupied territories of Ukraine".  That said, many Ukrainians would gladly cut the Donbas region loose, as it doesn't fit with their image of what Ukraine should be (i.e. European).