The problem for Ukraine is that if they don't launch it now, it would be too late to do anything during winter. And after the first winter, NATO may not be as willing to supply Ukraine with state-of-the-art weaponry come next year, they would have to do something now, because offensive takes time.
In a conventional term, an attacking force have to be have 3 to 1 advantage, or at very least 2 to 1, Ukraine did not have even close to that number, western intelligence believe Ukraine have at most 6 Brigade in this counter offensive, with 1 Brigade in reserve which mean you are looking at around 20k troop committed to this fight. If this was me, I would wait til I have 7 or 8 Brigade, tactically, Ukraine would try to encircle Russian troop in Kherson to try to win this without a fight, but if Russia did not budge, then I can probably foresee a Russian style take over, which is using artillery and rocket launcher to level everything and walks in and take the rubble. A frontal strike is all but ruled out.
I will say with a degree of certainty that Russia is going to lose Kherson, that's because there are literally nowhere the Russian can go, with all the bridges destroyed, there are no way Russian can be supplied, not to mention the logistic had not been well for the Russian throughout the entire war. The question is whether Ukrainian can do this with this counter offensive or buckle the Russian will to fight by constantly bombard Russian position over the winter if this counter offensive failed. That is the question to ask. But if it was latter, then the chances of Ukrainian having Western Support to pull another offensive is slim, Kherson may be the last counter offensive Ukrainian can mount, and they would have to settle with Russia in Negotiation in a long term.