Based on some comments in the article, it sounds like the guy is accusing Rockstar of financing a smear campaign. Maybe if they made a game that wasn't a straight GTA clone they wouldn't have to worry about something like that.
Ikaboze had access to a handful of save files at Nintendo Switch 2 Experience: Tokyo, one of which has a well-equipped Link that puts him right outside of Hyrule Castle. He makes quick work of Calamity Ganon.
So he just loaded a save file right before the end of the game. Not a speedrun.