Yeah, I can't find it anywhere on the VR app, it's either a licencing issue or an omission, as you say the games are showing on the website via the browser but don't play. I tried the Firefox Reality browser too and same deal, the play buttons don't work, so licencing is looking likely.
Only option is using the Quest with Link cable (or wireless streaming via Virtual Desktop) and watching the games via the Firefox browser on your PC (has to be Firefox) and stream to the headset via Bigscreen or Virtual Desktop (or Oculus Home on one of the screens available in your inventory).
Sorry, not much good if the Quest is stand-alone!
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