Need help making a special tool destroy a block that nothing else can but don't know how to make the procedure

i might have a solution, but I'm not sure i entirely understand... the block is unbreakable like bedrock? if so, you'd go into "when entity swings item" check if entity is a player, if it is, check where the player is looking (Id use raytrace distance x y z) and check if the block there is the block that you want, if so, break it and drop the block, or just replace it with air