Ukraine could easily be protect if there was a will to do so in the West. Very few people want to go die fighting for a country they can't even point to on a map so the the most effective solution to defending Ukraine is off the table.
This is definitely not the sort of "protection" I would rely on.
PRC sees the writing on the wall and, being the pragmatic bunch that they are, will probably not invade Taiwan. Unless Xi really controls the country 100% (this I do not know since I am not a Chinese observer) and goes crazy like Putin did.
I don't think Ukraine can win with the way things are going unless the West joins the fighting or Russia collapses. Waiting until Russia collapses will quite possibly be a long time which will result in a Pyrrhic victory for Ukraine. They will have an entire generation of dead men at the rate things are going.