Every powerful nation with significant regional muscle likes a buffer zone around it (Monroe Doctrine anybody?) - in fact as I've argued the Russian invasion of Ukraine was principally triggered by its slow slide from a kind of ambiguous buffer zone (providing both NATO countries & Russia comfort)......into something much more akin to a US/EU client state....ya know the type of place where the US Vice President's son is on the board of the largest company there.....and where a current US sitting president is so secure in his leverage over a sitting Ukrainian president (due to aid payments) that he can instruct him on a phone call to investigate a domestic political rival.
The great tragedy of Ukraine - is that we in the West put it so firmly 'in play' with our hubristic liberal democratic nation building dreams and superior economic resources vs. Russia....to be clear I'm not advocating for some kind of past Ukraine abandonment strategy where we ceded the country to Putin to become a Russian vassal state....I'm advocating for a Kissenger-esque balance of power strategy for Ukraine in the 2000's one where it was neither fully a Russian nor USA vaseel state......a strategic approach that never put it firmly in the Russian column or the West's column......put more crudely....just because you can afford to pump billions more of aid/economic investment into Ukraine than Russia could in the 2000's to buy their allegiance doesn't mean you should have. We failed at this game in Belarus might I add....seems all our love and attention was spent on Ukraine in this period.
That's ancient history - the correct strategy moving forward is to give Ukraine exactly what it needs to regain most of the territory lost with the highest priority placed on the economically important regions which allow Ukraine in the longer term to be somewhat self-sustaining economically and militarily. Some landlocked Oblasts in the East are not hugely important economically and due to Ukrainian populations fleeing there are no longer ethnically hybrid regions...they are simply now edge outs of Russia...pragmatism would suggest that these regions form the basis of concessions to Russia in the future.