Your opinions are much better thought-out than the most I have seen. I respect that. But you have several severe errors in your thinking I will try to convince you of:
1. Russia's military is not independent. FSB is above them. This "cutting the balls of the military" has been a long-term strategy. This is not comparable at all with the USA, let alone Turkey.
2. Military, power, strength resources are purposefully divided between different players, military does not have a monopoly on power. There are also FSB (with their own forces, judges, prison, killing teams), National Guard (have tanks), Private Companies (decreased/fractured after the Wagner debacle). Heck, Kadyrov's thugs are part of that equation as well.
3. There really aren't examples of successful coups from the bottom only.
4. No, I do not suggest negotiations with Putin, quite the opposite. Way more should be done to get rid of him and his family personally, and not pussyfoot around it.
5. EU's problem was and still is anemic, slow and stupid action (lack of). Damn morons.
6. No, a significant portion of the population does not support the war. Do North Koreans truly support their regime as witnessed by the voting results and by the fact that people are not protesting and are not organizing a coup?
7. Russia had Oligarchs, but doesn't have anymore. Oligarchy means that rich people can influence politics. In Russia they can't. The typical western "money brings political influence/power" does not apply in Russia. In Russia the rule is "political position (given by Putin) brings money (as long as Putin allows)". Businessmen have no independence. Check what happened to Tinkov (Tinkov bank). And he is the lucky one.