Let's backtrack a bit. Biden started the Ukraine-Russia war by agreeing to allow Ukraine into NATO (link). For years, Putin warned that any former Warsaw Pact nation attempting to join join NATO would be considered an act of war. Yet Biden gave the green light for Ukraine to join and Putin started planning the invasion of Ukraine immediately.
So before you ask if giving up Ukraine land is acceptable to the EU or Ukraine, consider: (1) Can Ukraine possibly WIN a war against Russia? And (2), does Ukraine, the EU or the US want the current war escalated even further?
Yes we know why Putin invaded Ukraine.
To answer your questions:
No Ukraine can't win a war with Russia without help from the West.
No neither the US nor the EU wants escalation.
The philosophy was to keep supplying Ukraine with defensive weapons to fend off the Russian invasion.
Hoping Russian would drain itself from public support, militarily and financially and quit fighting.
In jumps North Korea. That philosophy just took a dump. The escalation has taken a leap.
Rocket man has nukes.
So it looks like a compromise where Russia takes part of Ukraine, The Russian controlled part Donbas, was in Trumps mind.
Of course speculation on my part.
So the question is why did Biden let Ukraine use the offensive weapons that Ukraine has had now for a couple of years?
IMO the EU wanted to use US resources to drain Russia. Biden complied. Trump probably wouldn't have. He has said the killing must stop before the war escalates. He has said he would end the war. The only way to accomplish this would be to give Russia, what they really already control, Donbas.