Normally, to get games looking right in the headset, you have to manually tweak a games default settings like: FOV, resolution, or rendered shadows etc. These are often done through editing ini files from the games directory.
The games listed in the Settings Optimizer are ones that can have that work done for you automatically, once you click apply. True this list is small in comparison, but there are several games not listed that you can find how to do similar tweaks with a bit of googling.
Stranded Deep I’ve never played, and I don’t see it listed among Vorpx games. That doesn’t mean it can’t work, but that it like other unlisted games may never have been tested. Unless it shares the same game engine as other profiles, it may display in the headset, but likely wont work with desired 3D effect.