If Russia loses this war. What do you mean by that
Pretty difficult for me to imagine, in granular detail.
Local NATO brigade may find it hilarious - if one were to say that "Russia hasn't really begun to approach things seriously" - but in many ways it's the truth. Certainly the truth when compared to Ukraine.
1) Our government is terrified of calling a general mobilization.
2) The economy is still largely on a peace-time footing
3) Travel restrictions are correspondingly loose
4) UKR government offices are still strangely "off-limits"
5) Different "grain" and "ammonia" export deals are in effect, and gas is continued to be pumped through the Ukrainian gas transport network.
However, you asked me how we may lose... Here's how this might come about, IMHO:
1) Putin continues to think he may be accepted back into the warm embrace of G7, and therefore attempts to avoid doing anything "scandalous" - such as targeting key Ukrainian decision makers.
2) Putin continues to try to isolate Russia's civilian population from the "horrors of war". Eventually this will lead to a rude awakening, with unpredictable circumstances. Better to start preparing people now.
3) Martians land on Red Square, declaring eternal friendship to the people of Earth.
4) Zelensky declares as his aim the "reconstitution of the Soviet Union, within its 1991 borders", and calls upon the people of Russia and Belarus to lay down their arms in furtherance of this goal. The purpose being, the reunification of a single people separated by tragic historic events.