A temporary fix
Aspyr, the team behind the Switch port of Star Wars: Knights of the Old Republic II - The Sith Lords, has offered a workaround for a game-breaking bug that was discovered recently. This bug causes the game to crash after the Basilisk Crash cutscene when landing on Onderon.
Aspyr claims that a small number of users will encounter this bug, but that said, if you happen to be one of those players, you won’t be able to finish the game. While a patch is in the works to remove the bug completely, Aspyr has offered up a workaround via an in-game cheat code.
For now, the suggested workaround is to warp past the point where the game crashes using the cheats menu. To do so, triple click the left thumbstick, open the cheats menu, select warp, and warp to OND504. Make sure not to head to the merchant quarter, as your game will crash.