I am reflexively suspicious of any talk about “good” or “bad” defeats. On the one hand, such talk seems to echo fascist mantras of glorious deaths and sacrificial lost causes. On the other hand, there is a strain within the left—caricatured and perhaps exaggerated by centrist liberals, but for all that real—of left melancholia. This describes a certain posture that takes comfort in powerlessness in lieu of the difficulty of seizing and taking responsibility for power.
And yet, it strikes me as a question worth risking: what would it mean to fight for a good defeat—as opposed to a “bad” victory or, perhaps even worse, a bad defeat? What would a good defeat look like? I am led to pose the question in part because under the late racial capitalocene, most available realistic utopias will be at best ambiguous. But also because, as the United States and Israel seek to demonstrate in Palestine, our insurgencies of self-defense will be by necessity insurgencies against genocide.
I'd personally go with your initial instinct: to fight for or even prefer a "good defeat" over a "bad victory" is to capitulate in advance. A mistake that many on the left, and the Black left in particular, made previously and that may now prove impossible to undo.