Yakuza 8's name change was specifically for new Western players

The creators of Yakuza / Like a Dragon: Infinite Wealth, Ryu Ga Gotoku Studio, have given some explanation for the series title change

Kazuma Kiryu - Wikipedia

Yakuza 8 is now also Animal Crossing, apparently - Boing Boing

Like a Dragon Gaiden: The Man Who Erased His Name further details story, characters, and organizations - Gematsu

Yakuza 3 - Wikipedia

Interview: Yakuza: Like a Dragon Localization Producer Scott Strichart - Anime News Network

In Japan, it's still named Ryu ga Gotoku/like a dragon 8 : r/yakuzagames

Remastering Yakuza for the modern world

Three new Yakuza games and a name change - digitec

Ryu Ga Gotoku 8 Title Clarification Sparks Fan Debate｜Game8