If you want to play a battle royale Tetris game that is verified and often accessible where the official eShop version isn't, these are your best bets:
: The most popular modern alternative. It features smooth graphics, customizable controls, and "Tetra League" for competitive ranked play. tetris 99 unblocked verified
If you want to play the authentic Tetris 99 but are hindered by network restrictions, here are the legitimate, working methods: If you want to play a battle royale