I don't disagree with you. The conflict and the consequences are far-reaching and infeasible, with no good way back to normality.

But to Russian autocrats, this conflict is becoming a matter of honor. Putin (and probably his successor) will be committed to seeing this through, until the conflict reaches a state where a peace plan involving territorial concessions to Russia is acceptable to Ukraine and the west. I worry that the conflict will continue (and possibly escalate) for years before we've reached that state. At which point your scenario of insurgency kicks in.

The Russian objectives of the war have changed since the invasion began, starting with most of Ukraine under Russian control, then moving on to recognized annexation of the regions of Donetsk, Kherson, Luhansk and Zhaporizhzhia. Probably a Russian "win" would be recognized annexation of any of the above regions as well as a recognition of Krim as a Russian territory.

The question is if any of these objectives are compatible with a Western view of a Ukrainian "win", which so far amounts to reverting to pre-2014 borders.

The diplomatic and political price of a Russian win, however, looks like it will be very high and will affect regional safety politics for decades to come, firmly estranging Russian interests from the western world

This statement reminds me of Aesop's The Frog and the Ox