If you are using the Vive Cosmos and you haven't already created your own custom input bindings, you may find that your controllers are not able to move in the game. The public_testing version now includes default bindings for the Vive Cosmos.
The bindings still need further testing, but if you want to switch to the public_testing branch and try it out, you can do so in the "betas" tab in the game's properties window. If you have the Cosmos and can use it in the public_testing branch, please let me know how it goes.
Thanks!