Only Russia can de-escalate the situation.
The irony is that Russia could have taken Donetsk and Luhanks and the war would have been out of the news cycle by now. The West would just have repeated the harmless 2014 targeted "sanctions" on Russian oligarchs and politicians.
Putin's and Lavrov's genocidal speeches about Ukraine being a fake nation that should be "de-nazified" and the Russian attempt at taking the capital Kyiv has escalated this conflict into its current state.