Ukraine retaliation?

Actually they have shelled smaller cities and allegedly hit a munition plant close to the border(or maybe was sabotage within Russia).

It would purely symbolic, and if anything would piss off Russians more, which is not a good thing since they haven't had great deal of motivation in this war, or nearly enough to match Ukrainian's.

They hit a Russian airbase with ballistic missiles and shelled a few positions. They can’t afford to expend precious resources on attacking Russian land when they need to focus on taking back lost territory and don’t want to feed Putin’s justification of war.