Not being able to take the territory, having a ceasefire over the territory, and actually conceding the territory are three different things. The world is full of unceded occupied areas. Korea. Taiwan. Northern Cyprus. Palestine. Nagorno-Karabakh. Transnistria.
Ukraine rightly has no interest in ceding land to achieve a temporary ceasefire to allow Russia to re-arm and then attack again.
Meanwhile it is also important that we don't have two nuclear armed states (France and Russsia) officially at war.
I'm not excited to have France and Russia in direct conflict, but having two nuclear states at war would not be anything new. There's been China/USSR, India/Pakistan, India/China, and if you want to consider wars that mostly exist on paper at this point, North Korea/USA.