The solution is simple, turn Gideon back into a baby.
That would make sense, but I’m assuming they’ll “explain” that possibility away by saying Gideon is too powerful to be affected by that type of magic. Or, the characters won’t think of the baby solution until the season end/finale when it’s time for Gideon to be defeated. They’ll also realize Regina needs to reintegrate the Evil Queen in the same episode and it will be titled, “Why Didn’t We Think of That Before?” or simply, “Duh.” Or maybe one of those can be 6B’s tagline. Lol.
Or “we could have ended this horrible plot 12 episodes before but needed time to waste on Regina moreso then we already do meanwhile what’s an Emma flashback? Here’s 20 more Regina ones.”