For almost 7 years Odo was committed to justice above all else. Then in Season 7, out of the blue, Odo goes totally out- of-character and forsakes his commitment to justice for the sake of instead worshiping plot contrivance, while holding blind loyalty to Federation murderers. That happens when Odo-indefensibly-agrees with Sisko to do nothing to stop the Federation's genocide against the Founders.
The ending in WYLB is an equally ludicrous extension of that ludicrous, character-bastardizing plot contrivance.
As a person who holds justice above all else, Odo would rebel against the genocidal Federation, and lead the second wave of the Dominion War a short while after he goes to back to the link. He would convince himself of that, and all the Founders would support him.
Odo would have no reason to have promote pro-solid propaganda to the Founders. Only a totally different character, a new Odo that bears no resemblance the Odo that was featured for 95%+ of the show's screen-time, might do that.
Even if he did, they would never accept it. At most, Odo could say he met a few decent solids. But that pales in comparison to the fact that the solids are genocidal maniacs who have confirmed through the genocide disease everything that the Founders already believed about them.
In other words, none of Odo's cutesy stories about a few decent individuals could ever overcome the fact that on the whole, solids are mass murderers.
Ergo, the question in the OP depends on which frame of reference one wants to go with.
If we are talking about the true Odo character, he would cure the Great Link in 2 minutes, spend a few months planning war strategy with them, then come through the wormhole with the full force of the Dominion and take over the AQ.
If we are talking about the mindless drone Odo character, he would spend a few months in the Great Link, and then, extending the writers' absurd logic, all the Founders would magically become mindless drones too, overlook the Federation's attempt to wipe them out via genocide, and love every solid for the rest of eternity.
