It's fairly well-known that you can launch SteamVR on it's own, without Steam, and quite a few SteamVR users typically do this for any game that has VR but is not a Steam game (me being one of them). However, I have discovered that Odyssey does not like this, even if it's a non-Steam version of the game. I'm using a Valve Index, and, if I run SteamVR on it's own, then launch Odyssey, even on the 'low' graphics preset, it's a juddery, stuttery, unplayable mess any time I get close to a planet or station, even though I do have a bit of a beast of a machine (Ryzen 5900x, 64GB DDR-3200 RAM, 2TB NVMe SSD and a GeForce 3090). However, if I launch Steam, and launch SteamVR through Steam, then launch Odyssey, everything becomes as smooth as butter, even putting all graphics options up to full (except for supersampling and HMD image, which I leave at 1.0).