Back to negotiations topic.
Currently negotiations are not possible. Donbass is not yet fully liberated, so one of officially declared Russian objectives is not achieved. Until then Moscow is not willing to sign a ceasefire agreement and try to fulfill its remaining objectives by negotiations. I even think military operation will continue after Donbass is cleared, to have some territory as a bargaining chip (like it was with parts of Kiev, Sumi and Chernigov regions which were cleared after Istanbul negotiations - Russian army didn't tried to set military administration there).
Kherson region and part of Zaporozhye region are no longer such bargaining chips, and Ukraine will have to cede them if they agree on second (future) Putin's offer.
Ukrainians also not willing to agree on Putin's demands since they got support from West and still have manpower to use supplied weapons (how proficient this usage is another question). So now they are trying to create a decisive numeric superiority with enough artillery and air support (from Western supplies) to launch a major offensive operation with aim to kick Russians out of Ukrainian territory or at least inflict heavy losses to Russian army so it won't be able to launch any offensives itself.
In the meantime they trading barely trained conscripts and some towns in the east for time to receive Western equipment from lend-lease and train another portion of conscripts and some professional soldiers to operate said Western equipment.
They probably bet everything on this since if this fail, they will loose all trained troops, most of equipment and ability to bargain any good deal for themselves. Third offer from Putin will most likely include Odessa, Nikolaev and Kharkov.
Also it should be noted, that Ukrainian ability to fight protracted war entirety depends on Western support. Ukrainian economy is toast and on life support from West (which is not infinite). If they want to survive as state they need to finish this war till winter one way or another.
