Advisors who always insist on one particular idea: How to deal with this?
One suggestion is to use a kind of "red herring" strategy: Work on two directions in parallel.

The one direction is the idea that your supervisor wants you to follow, and that you will mainly discuss in meetings, thus giving him the impression that you buy into his game.

The other direction is the idea that you think will actually lead to results. The time to first mention this direction is when you have made some substantial results - you may then calmly announce that you plan to submit them to a specific publication venue.