I started with 0 and worked my way chronologically from there (with the remakes for 1 and 2), and 0 is my pick for best if the series. I think the thing to know about the real estate sub-game, and others of its ilk like the host club in the same game (I think), is that they are completely parallel, non-consequential, optional content.

I personally feel that you could go through every single Yakuza game playing only the main story and side stories without missing anything of value. I would frequently force myself to play batting cages or karaoke or dancing because fans talk a lot about that stuff, but there’s really very little there to compel your attention unless you enjoy it. You can totally skip all that.

You could probably also skip the side stories if you just want to follow the main path, but those I do think are more crucial to Yakuza’s experience and identity - the outrageously silly flip side of the coin to the main story’s soap-opera-esque melodrama.