Ukraine deserves all the success in the counteroffensive in the Charkiv region. Also, those new ideas for security guarantees published recently are a promising sign. At the moment things are going well for Ukraine as they should be. The skill and will of the Ukranian army is quite something. On the other hand the hasty retreat of the Russian force even included elements of panic. Ukraine could now keep Russia guessing and either cross the Oskil river or attack in the direction of Berdiansk or ramp up the pressure in the Cherson region.
At the moment, it looks like the defenders are in a position to kick the rotting door down, de-occupation looks like a real possibility for the first time in case the panic in the Russin army spreads like an ember. There is no way of knowing, but we're seeing first hints.
Would it be an acceptable compromise for a peace agreement that Crimea - at some point in the future - be divided? The western half for Ukraine, the eastern half for Russia? (Plus a new Berlin Wall in Sevastopol? An absurd idea, but maybe not the most absurd one on the way to find some kind of solution for this horrible war.) An alternative -- depending on how the situation develops -- would be for Ukraine to get back the whole of Crimea but, as before the war, give the Russian navy certain rights in Sevastopol. However, we must bear in mind that because of the Russian atrocities in this war, any concessions regarding Crimea would be very generous from the Ukrainian side. (The best thing anyway would be for Russian society to come to its senses and accept a complete withdrawal without any territorial claims.)
Apart from Crimea: Russia should return all other occupied territories soon, pay reparations and (ideally) assist with a Nuremberg II.