Mario Skins and mashup pack inaccessible offline

Switch version of minecraft has been getting progressively worse with every update when it comes to offline play. Before, I could access the mario skins and world offline, but now I have to be connected to the internet in order to access the mario skins and world even though it's supposed to be a built in add-on that doesn't require a connection. It's been like this for YEARS and is still unresolved.