I don't think giving just enough help to keep things at a standstill is particularly positive.

That's your problem right there; the stalemate situation is well... it's not ideal, but make no mistake it's advantageous for Ukraine. Russia's military is much bigger and better equipped (when it comes to the big stuff anyway), and unlike Ukraine they don't have dumb conditions attached to their weapons. However, Ukraine has one advantage compared to Russia: the purse. As long as Western support lasts, Ukraine has nearly infinite logistical and financial aid to help prop it up while it fights the Russian invasion. This gives them a massive advantage in a long battle of attrition, which the current stalemate is, while Russia's economy declines and its ability to sustain the war effort decreases. The result of all this is that Ukraine's position will improve as time goes on, so even if we assume that they'll eventually be forced to take a Russian peace offer it makes sense to delay that as long as possible so they can increase their leverage when they go to the negotiating table. This, of course, does come with the price of Ukrainian soldiers dying to sustain the war effort, but so far it seems like Ukrainians are willing to pay that price.