Zelenskyy rejects the foundation of the US-led peace plan, saying Ukraine will never accept the idea of Russia keeping Crimea.

Now, remember that Russia annexed Crimea a decade ago, in 2014... - John F. Di Leo

...back when Obama was in the White House. (and the West's idiotic response to that annexation is one of the things that led to the economic downturn that followed, as we started issuing idiotic sanctions on Russia that only hurt the USA and Europe, without hurting Russia at all).
We might not be surprised if Ukraine objects to some maps in which Russia takes part or all of the Donbas etc. 

But Crimea? 

• They had Crimea eight years before the 2022 invasion!...