The Starling 2 and Starling 2 Max will be supported for the foreseeable future. The Sentinel is less popular, so it is likely to be deprecated in 2025 but is currently marked as "Active Production" on its website
Dash speed, or burst speed, is the airframes capability when full throttle is applied for a short period of time. Batteries are typically able to discharge more current when first applied, but not for a sustained period of time.