The Ukrainians could fire an American M777 right now into Russia. HIMARs as well. Ukraine has and still does shell areas or hits areas along the Russian border.
You have a Pentagon looking at a possible proposal by Boeing to provide the Ukrainians longer-range weapons.
https://www.commondreams.org/news/20...ssiles-ukraine
The Russians don't seem willing to negotiate a peace without Ukraine accepting that it annexed those four regions. Obviously it's a non-starter. Russia's not going to budge on this unless forced to. Having your supply lines, airfields, bases, and troops bombed or shelled while in home territory might just cause them to budge. Otherwise it's just going to be one long grueling offensive after another with the Ukrainians slowly clawing back the territory they lost. How long do you think that's going to take?