I don't think we're ever getting rid of all three, the point will be mitigating them to a point where we're functionally on par with a faction that isn't crippled from the start. But yeah, I think every faction's gong to have their own path to get there, the only one that likely requires unified support is the Isha Heist.
The name of the game is mitigate, workaround and rules lawyer. We already have examples of the various workaround that Canon Eldar use to avoid the slannesh soul eating.
Actually lifting the curses are going to be the work of legends, hundred, possibly thousand year epic struggles to lift the curses considering the criteria we are looking at, of which permanent killing the champions of one of the chaos gods is the simplest.
But the biggest upside of the knowledge of the curse, is that Eldar as a race now not only know HOW they are under attack, and they have more then just soul eating they will need to mitigate, the Eldar race has WIN conditions again. They now have goals besides "don't get eaten by the soul bad toucher"
They know they can clear their sight by killing kairos, so kairos is now a racial Target. They know Isha is alive, and rescuing her stops nurgles curse, so they now have a goal, a rescue mission, he'll they now know how much slanneshes curse is bound to the seat of the Phoenix court, who Isha also can upsurp.
Eldar have a GOAL, and a win condition, instead of just trying to find ways to survive that bit longer and not get soul eaten. A goal and a win condition can be a powerful thing to a person in depression.
Actually lifting the curses is a long way off, but one can't understate how important the knowledge that they CAN be lifted is, both in terms of mitigating the other two curses, but in terms of affecting the racial psyche of the eldar.