While the Internet Archive does host some legitimate Mario Kart 8 Deluxe
Prototypes: There are occasional listings for Mario Kart 8 Deluxe Prototypes which are often uploaded for historical preservation rather than as playable "final" retail games.
The Future of Game Preservation
Mario Kart 8 Deluxe ROM Now Available on Internet Archive
You can find a used Switch Lite for $100 and a used Mario Kart 8 Deluxe cartridge for $30 on Facebook Marketplace. That is $130 for a flawless, portable, online-enabled experience. No viruses. No crashes. No DMCA fear.