Source on the thing about Nuland owning/running/operating the ISW? Not heard it before. Not saying you're wrong of course, just genuinely want to learn more!

With regards to the rest of the post, I don't think the conflict is as divided on ethnic lines as you have said. The invasion has been largely opposed by Russian-speakers in Ukraine from all data I've seen, e.g., in areas like Kherson there was massive anti-Russian resistance and a huge swing towards Ukraine. Plus I don't think supporting joining this or that economic bloc or voting for Yanukovych implies outright support for secession and DEFINITELY not invasion. Even if there is real support for Russia in the Donbas region, that still isn't a divide on linguistic/ethnic lines considering the rest of the Russian-speaking part of the country has rallied behind Ukrainian state leadership.

Honestly I don't know popular sentiment in the Donbass and I don't want to make claims beyond the limits of my knowledge, but I do know that the more independent-minded leadership of the D/LPRs were replaced by pro-Russian ones from the 2014-2018 period and that it's quite obvious Russia had a huge role in supporting them, propping up their political leadership, and militarily supporting them from the start. I think Crimea is different as there was way more genuine desire to secede to Russia even before 2014 (though I still think the referendum was rigged as polling beforehand showed a smaller percentage wanting to join-still way over 50% though).

In reality the war has frozen because the correlation of forces is balanced. Neither side will or can win or even move the front lines significantly. I just don't think either side has realised yet. Neither is close to breaking point atm. Russia couldn't even take Bakhmut, and Ukraine cannot make any ground even w/ new western tech in their supposed push towards Melitopol. No winners, only losers.