A protagonist should solve his or her problem personally, not just stand by while someone else does, although there may well be many people working together that achieve the solution. But the "defeat of the villain" is not always the real issue for the protagonist. Sometimes the villain or antagonist is merely an obstacle, and the real issue is something else, perhaps a character issue.
Consider The African Queen by C. S. Forrester (the novel, not the movie version). It would seem that the task of Charlie and Rose (the co-protagonists) is to destroy the German patrol ship Louisa and thus end the German lock on the key travel route. But at the end the Louisa is sunk by a British armed cutter, and would have been in exactly the same way had Charlie and Rose died half-way through their trip.
The real victories are ones of character and habit. Charlie changes from a somewhat lazy go-along, get-along person to one able to tackle problems that are almost insurmountable with energy and good humor. Rose changes from being dominated by her brother to being able to plan and force through prodigious efforts, and to more or less run Charlie. And the two come to love each other, and learn to work together. Those are the issues that they solve, and the destruction of the Louisa proves essentially irrelevant.
Or consider Shakespeare's Macbeth. Macbeth is the protagonist, but also arguably the villain. He has no ultimate victory, and is destroyed in the end. He could be called an anti-hero. He is a very active central character, however, and the play generally works well. What he does achieve, he achieves largely through his own efforts, including his own final defeat.
In your work, if the protagonist is not going to be the one to "destroy the villain" then there should be something else that s/he does achieve, that can become the real point of his or her efforts, even if s/he did not know what the point was, at first.
There are stories where the central character is more of a witness to events than a mover of them. In many such cases, there arguably is no true protagonist at all. That can work, but many readers now find such a design unsatisfying, and such stories are out of fashion now, so one must be particularly well done to succeed.