With no prior experience of Yakuza I did see an LP of 4, but forgot like 95% of it besides who the 4 main characters are and the final fight.
Yakuza seems cool but i have no patience to catch up on all of those games. Might give 0 a chance just because its a prequel and won't have any baggage with it.
And its also on PS4.
Every game so far came with a video to catch you up on things. They do a good job with it I think.