so many unknowns but the biggest one by far is western support Ukraine started this war with very little ....only fairly recently got longer range missiles and very recentyl ATACMS with F-16's yet to come
on the other hand russia is having to buy from N Korea and dig out old tanks and rate of artilery fire dropping right off . shows russian production while useful isn't keeping pace
If western support continues near current levels I can't see how russia can match that and outspend / outlast the wests resupplying of Ukraine . If not Ukraine will lose at least some of it's territory . So IMO depends what the US decide on funding and if Europe are able to pick up the slack (if needed).
One thing in the back of my mind is countries not wishing to "give" more to Ukraine might "sell" more and some of that perhaps on borrowed money but that is conjecture .
I don't think it comes down to troop numbers but that is a possibility too .
