Yup. Be a good neighbor and join the Little Entente with a firm alliance with Czechoslovakia etc.
A change to Polish foreign policy alone cannot achieve that, for reasons pointed out above.
How achievable was a settlement over Galicia and Lviv? Just assuming for a moment that the West Ukrainian People's Republic and a Ukrainian People's Republic made up of say the land to the west of the Dnieper somehow managed to hold eastern Galicia and Lviv would a serious peace deal with Poland be possible? Nationalist sentiment seems to have been ridiculously high that suggests tensions might of broken out again later. It would of certainly helped the Ukrainians though as IIRC it would of meant they could of continued swapping oil from the Drohobych oil fields for Czechoslovakian weapons and ammunition.
Tensions would break out later, no side would accept losing the city.
In OTL, there was an Entente attempt at arbitration between the fighting Poles and Ukrainains.
Here's a map:
The orange-ish line is Ukrainian demands. Purple line is Polish demands. Red line is the compromise proposed by the French general Joseph Barthelemy. As you can see, it has Lviv/Lwów as well as the Drohobych oil on the Polish side. Additionally, 50% of the oil revenue was to go to the Ukrainians.
The Poles were willing to accept that, but the Ukrainians rejected it, feeling confident (they controlled most of this territory). There was supposed to be another attempt, and they even signed a ceasefire, but eventually it all went to shit. Poles destroyed the WUPR, and when Piłsudski formed his alliance with Petlura, he was the one who could confident, and got all of Galicia - which made Petlura look even more like a Polish tool.
IMO one of the better (as in: marginally plausible) ways to achieve this would be if both sides grudgingly accept a compromise line offered by the Entente (either the Ukrainians feel much less confident, western Ukrainians have much less say in this decision, or the line is different and easier to accept for them), and it sort of sticks, because while neither side would be content, they wouldn't want a war.