Skyrizi is specific for IL-23 and Stelara is specific for both IL-23 and IL-12. However, it is thought that the anti-IL-23 action of Stelara is doing the heavy lifting in battling the Crohn's inflammation. The anti-IL-12 activity appears to be just along for the ride, so to speak.
Given all that, why would Skryizi work any better than Stelara? Logic suggests that it won't, but we have the example of Remicade and Humira that both bind TNF and similarly should work just the same in treating Crohn's. But we regularly hear from patients on this forum that experienced good success with one but not the other, and vice versa.
In addition, despite their similar specificities, Skyrizi recently out performed Stelara in successfully treating IBD in a head-to-head comparison clinical trial.
With these two factors in mind , it might be worth a shot to give the Skyrizi a try. despite the earlier failure with Stelara.