At the risk of repeating myself, “Finlandization” of the Ukraine is the most likely outcome of this war.
The country will likely retain control of its internal affairs, but will have to follow Russia on all matters of foreign policy.
(After also having surrendered a significant part of its territory).
There are parallels:
In the “Winter War” of 1939-40, Finland punched well above its weight. However, in the end, it was the Russian juggernaut which prevailed. By the time it was all over (late in 1944), the Russians had had sufficient of a bruising that they did not attempt to occupy Finland. Instead, a rather punishing treaty was negotiated.
(Similar, too, to how, in the days of the Indian Empire, Britain dealt with Afghanistan. After a number of inconclusive or even humiliating military escapades, they did not attempt to annex the country. Rather, more subtle means were adopted to influence events).