If you want to play The Rebel Collection on your Switch without legal risks:

Often overshadowed by Black Flag, Rogue bridges the gap between Black Flag and Assassin’s Creed III. You play as Shay Cormac, an Assassin-turned-Templar hunting his former brothers in the icy North Atlantic.

If you have downloaded an Assassin’s Creed The Rebel Collection NSP and encounter a black screen after launch, here’s why (for educational purposes only):