Critique the literature on situationism with classical comments on the possibility of moral improvement i.e. should we be surprised that relatively minor, individual-focused interventions/experiments failed to have any noticeable effects.
Alternatively, you might agree that pretty much everyone’s mood is greatly impacted by random shit, but self-cultivation can still be effective, since it determines the direction of drift. There’s a lot of random noise in what determines our everyday decisions, but if you have an abiding wish/hope/plan to be better, this gives a kind of positive momentum. For this to reliably shape your character and ensure free will The sociality of personhood, moral knowledge, and responsibility most decisions must have small consequences that slowly but constantly compound. Massive, decisive choices make things too noisy. Cope?