Disney Speedstorm does not officially have a status for Steam Deck right now, but we can see it being verified in the near future.
Disney Speedstorm runs at 50-60 FPS even with a tonne of weapon effects going off on screen and sliding around at 100+ mph.
The offline campaign is pretty lengthy and holds mostly 60FPS
While online multiplayer can be a bit more taxing hitting as low as 50 FPS
Although you can play Disney Speedstorm offline, you will be restricted to local freeplay only, you have to be online even for the Single player campaign, hopefully, they will change this for the full release
Disney Speedstorm will be free to play once it leaves early access, but for now, you will need to get one of the founder's packs to dive in