There were tons of attempts of negotiation. So mich that the long table became a meme. But if a party has aims which are unacceptable for the others, there isn't much negotiations can lead to.

Right, by negotiate with Putin he means accept whatever terms Putin demanded.

Russian displomats demanded denazification of Ukraine. When pressed on the details, they didn't know what it meant.

They can't know because they have a paranoid, ramblish (did you see the recent speech?) geneatric emperror and slave-ish, self desteuctive subservience.

One does not simply negotiate with the Russians. It only works until after the've been beaten them and they have their back to the wall.