There is definitely propganda on both sides (and how much of it is true is hard to tell). Russia isn't the only one with a propaganda machine, if anything the US is much more successful at it than Russia could ever hope to be.
I encourage you to read more of the Quora article, even if I appreciate that some of the stuff in the article might be hard to stomach, since you seem emotionally closer to the issue than I do. I believe a lot of it is very unlikely to stem from Russian propaganda.
Some of the stuff you attributed (eg you mentioned tribalism and spite) to Russia isn't unique to them or their politics; it's just a very primitive part of human nature that we still struggle with.
And to close with a tangent: it's always good to keep in mind that nobody (neither you or I) is immune to propagand; especially when it's pushed by state actors with a larger agenda. This is why I often indulge in reading stuff I don't agree with (within reason). Does give me a bit of cognitive dissonance occasionally, but alas.
There's zero excuse for Russia's invasion of Ukraine. I don't even see how this is semi-debatable.