They're trying to dissuade European NATO members from continuing their support for Ukraine.

Things are going badly for Russia. The war has lasted longer than the Great Patriotic War against Nazi Germany and Ukraine is actually taking back territory. Over half a million Russians are dead and probably a million wounded. The economy is imploding due to the enormous expenditures (30% or more of GDP is spent on the war). Just like in WWI Russia is running out of men to continue the fight. It either has to give up or escalate.

I believe Zelensky made a big mistake insulting Putin when things were going stellar at the front a couple months ago. By making it personal Putin is doubling down until he defeats Ukraine or Russia is destroyed in a war with NATO.