There is no love between the Ukrainians and the Russians. Putin wants a civil war. The Ukies will not get any support from the pussies in Brussels or the White House. Russia will dominate Ukraine, and there will be another world war. The Ukies know very well what Russians are capable of. They are fiercely nationalist and will fight, but I do not think they have the resources to beat Putin.
This could get very ugly very soon.
If they get a few billion in cash and equipment per year, they will beat the Russians. If they don't, they are gonna lose. But Stepan Bandera gave the Russians a run for their money back in the 40's and 50's, his was a shoestring operation with no support from the state. I expect the Ukrainians will give a good account of themselves even if they have to fight with no outside material aid. Still, it would be a pity to appease Russian imperialists.
I agree with most of what you’ve said but think back to Georgia. This is the same plan. Breakaway republics. Russia leaves Kiev alone, most of the Ukraine but separates what they want and nobody will do a thing about it except maybe the Ukrainians themselves.
Who is most likely to help? A few nations like the Czech republic and Poland? Germany? France? Never.