You are correct that there were more demands than the one I referred to.
The point I was making was that Ukraine sadly appears to be devastated by this war and is arguably worse off today by the choice they made to engage instead of finding a peaceful solution.
I don't see any mention of Russia being invincible in my comment - little confused by your comment there.
I am stating, however, that it is increasingly obvious that Ukraine is running out of young men to fight with. A quick internet search gave me these results:
"The average age of Russian soldiers in the last two years is not explicitly mentioned in the provided search results. However, it is noted that at the beginning of the war in Ukraine, the average age of Russian soldiers was reported to be 20-25 years old. Additionally, there is a mention of reports indicating that the average age of Ukrainian forces is around 43 years old"
This is an increase of between 27% and 43% depending on how you calculate it, in the age of Ukrainian soldiers over the last 2 years. Not a winning proposition.
Under those circumstances, donor countries like the US will either have to provide their own young men to die supporting Ukraine, or provide more expensive weapons to a country that has continued to lose ground in spite of the weapons we did provide.