Let's take a look at a few slides from this lecture that Mearsheimer gave back in 2015 to get a bit of background on the subject. Mearsheimer is a prominent American scholar who is not pro Russian in any sense. First, here's the demographic breakdown of Ukraine:

here's how the election in 2004 went:

this is the 2010 election:

As we can clearly see from the voting patterns in both elections, the country is divided exactly across the current line of conflict. Furthermore, a survey conducted in 2015 further shows that there is a sharp division between people of eastern and western Ukraine on which economic bloc they would rather belong to:

If you believe in self-determination then presumably you think Alexei Navalny should have been able to run in Russian elections?

No, I don't think open fascist should've been allowed to run in Russian elections. https://archive.org/details/VideoAlexeiNavalnyComparesMuslimsToCockroaches

Presumably you think he shouldn’t have been poisoned by the FSB?

Presumably you know something that Ukrainian intelligence doesn't? https://www.kyivpost.com/post/28630

It's hilarious that you think FSB poisoned him with intent to kill him, then for some reason let him go to a hospital and fly to Germany. This would make perfect logical sense to somebody who's high on meth I suppose.

Nor was Navalny ever a popular candidate. The most national support his party ever got was only around 5%. This was never a serious party. So, again, it's not clear why anybody would think that FSB would need to poison this fascist pig.