Random thought I just had: the Cubs should buy low on Freddy Peralta and then turn around and buy high on Mason Miller
Freddy Peralta is probably fine, but even if he's not he's been good for one time through the batting order this year before the wheels come off. Ditto Edward Cabrera. David Peterson has historically been a guy who, even when things aren't going the best, is good the first time through. Ditto Colin Rea. Ben Brown can, at minimum, presumably make it back at a lower volume role this year. Ditto Justin Steele. Jaxon Wiggins would absolutely eat for 2-3 innings at a time. Etc. Etc.
There is a good chance you end up in a good spot with the rotation. It obviously won't be all sunshine and rainbows with the SPs going forward, but between Peralta / Boyd / Shota / Cabrera / Brown you probably end up with three guys throwing well as SPs heading into October.
And if not? Embrace chaos and just bullpen your way to the promised land. Combine half a dozen multi inning relievers from the list above with half a dozen typical short relievers (Miller, Palencia, Webb for leverage; Rolison, Thielbar, Ferguson for matchup work) and just let Craig and Tommy cook. It's 2026 you're probably not counting on more than 4-5 innings from any SP in the playoffs anyway. Just lean into it.