What organization or country would be able to pull off successful peace negotiations between Ukraine and Russia?

So far there have been many failed peace negotiations between Ukraine and Russia. Why is that?

The three most common problems of failed peace negotiations are according to my netsearch: “mismanagement of expectations; unwillingness to emphasize: and lack of preparation”. I guess "emphasize" means that each party should have a priority list?

When I first saw the word "emphasize" it thought it said "empathize", but I realized soon that that was not what it said. I don't know if it would be good to empathize with an enemy in a situation like this?? Maybe it is possible to empathize with the first entries on the enemy's priority list?

One could ask if the peace negotiations that has been held so far were held by professionals, or amateurs? Who would have the best expertise to perform a successful peace negotiation between Ukraine and Russia? Would it be the UN, the Red Cross, the Vatican, Switzerland, US, China, or some other party? And why would that be so?