You've obviously put some thought into my position here and tried to understand it, so I will do my best to return the favor.
Realpolitik is certainly prevalent, and my country is no stranger to this. Words on paper are only as good as people's willingness to do what it says. I completely agree that the majority of the time, "rules-based diplomacy" just means gunboat diplomacy with extra steps. However, that veneer of western justification at least kept the absolute worst impulses of imperialism at bay, even if just a bit. That "just a bit" part is important, because as you quite rightly say, new material conditions will result in new possibilities. What the result of those possibilities are is important. They directly affect my life in substantial ways.
The point about lessons and thinking about this in purely academic terms is difficult when you have friends and family of friends sucked into the conflict. It's very difficult for me to engage with a point as academic as this being so close to the conflict. I know that is an admission of a lack of impartiality and perspective, but it's the honest truth.
As I said in another comment in this thread, I see Russia as more fascistic and right-wing than Ukraine. So in my head, what you're saying with that final sentence is "Ukraine is forced to reckon with its right wing, fascistic side by being stuck between the global hegemon and even worse right wing fascists".
I think another point of contention here is that I have a fundamentally different understanding of what the word "fascist" means compared to you, which I'm glad you've identified and tried to rectify. Maybe we're just talking about different things. I'll read that essay when I have the time, and hopefully the next conversation I have with you I'll be a bit more capable of talking with common terminology.