It is extremely unlikely. Samsung do not support allowing access to the full security feature set with alternative operating systems on their devices https://twitter.com/GrapheneOS/status/1640848564191473665 (https://nitter.net/GrapheneOS/status/1640848564191473665). Market share would usually become a factor if the device is already suitable.
The GrapheneOS team does plan to support Google's Pixel Tablet https://twitter.com/GrapheneOS/status/1635963398289498114 (https://nitter.net/GrapheneOS/status/1635963398289498114) which may target a lower price point than Samsung's Galaxy Tab SX devices.