I mean, I think it's quite obvious that he's cocked up the entire season. There's no denying it, though as I said, I think we can argue endlessly as to what degree. The question now, in my mind, is where does he go from here? More importantly, if the rumors of him exiting next year are true, where does Who go from here?
Well I'd definitely completely change things, but on a more immediate not here's how I think things could get more interesting for S12. Of course, it may come across as just a silly fanfic.
As much as I think Graham is the only good companion, he needs to die, for Ryan's sake, just as Ryan and Graham are really starting getting along as father and son, fist bumps included. Ryan is consumed by the need for revenge and takes it out on whoever killed him (Daleks?) (following up on his Call of Duty moment), and the Doctor feels shame over the death of Graham, the death of Grace, and now what's happening to Ryan. Graham's dying wish is that 13 keep Ryan safe, and she feels she can't keep Ryan on on the TARDIS anymore. She drops him off back at home, now orphaned, and Ryan can't forgive her.
After Graham's death, 13 becomes more committed to saving people, the rules be damned. Yaz stays on with the Doctor and enjoys the power of policing the galaxy, something she doesn't get from issuing traffic tickets in a small town. She continually pushes her to interfere more and more drastically in history (Time Lord Victorious), until in the finale some major crisis in time happens, the kind that the Doctor is always worried about will happen if history is interfered with too much.
Throughout the series, the Doctor is being tracked by enemy time travellers who turn out to have good intentions, as they want to stop her from destroying time itself, and they trap her on Earth with the help of Ryan.
Through time shenanigans, Ryan's arc concludes when he meets his mother again, who convinces him to forgive and let go of his anger.
The Doctor sacrifices herself to fix her mistakes and put time back in order. She regenerates and a new showrunner takes over.