Russia leaving is apparently never an option when they talk about possible solutions

Yes.. it isn't. Thats how reality works. Russia isn't going to just up and leave. They aren't going to have thousands of their own people killed and then just... nothing. They have goals, they want to meet them, and if not then at least get somewhat of a victory. The people in Russia aren't going to like "oh, we just left". I don't fucking understand how people can say "the war ends when russia [just up and leaves]". This isn't fantasy land, that isn't how it works. Russia will leave, if Ukraine negotiates a peace with them. If Russia wants land then UK has to negotiate for that not to happen.