Minsk was the peace plan to Donbas' rebellion. The choice for Russia was between Minsk agreement and all-out war. They had made this clear. For whatever reason the West decided to ignore that.
Speaking to German news agency, Merkel defended her Russia policy but said she failed to influence Russian President Vladimir Putin
www.news18.com
Former German chancellor Angela Merkel in an interview with German news outlet Der Spiegel defended her policy towards Russia and said her stance on Ukraine during the Minsk peace talks bought Kyiv time to fight Russia better.
Petro Poroshenko said the Minsk agreements “meant nothing” and claimed credit for giving Kiev enough time to militarize Petro Poroshenko has admitted that the 2015 ceasefire in Donbass, which he negotiated with Russia, France and Germany as president of Ukraine, was merely a distraction intended...
thepressunited.com
Petro Poroshenko said the Minsk agreements “meant nothing” and claimed credit for giving Kiev enough time to militarize
“We had achieved everything we wanted,” he said of the peace deal. “Our goal was to, first, stop the threat, or at least to delay the war – to secure eight years to restore economic growth and create powerful armed forces.”
So, for whatever reason, both Ukraine and West merely feigned to have talks, they were never serious about it. It's likely that neither of them expected Russia to escalate to a full-blown war, something Russia had already warned about. Or the West, in particular the US, assumed that Russia will take Ukraine easily and that will be followed by a low intensity conflict that will bleed Russia over many decades.
My thinking is the US wanted Russia to invade Ukraine, so the follow-up sanctions during the war would cripple their economy entirely, leading to separatist revolts. But what stopped that from happening was India rapidly buying all the freed up oil and acting as a hedge against China. It's also why the US came down heavily on India at the start of the war, and had to back down after we didn't relent. During this time, both the French and the Germans were in la la land, had no clue what was happening. They probably thought investing in the UAF would act as a deterrence against invasion, explaining the ouster of the French intelligence chief after Russia invaded. And Ukraine probably thought their new army will give them the ability to take back Donbas and Crimea.