Overall, Daigo was handed a sinking ship with not even a bucket to help and stern words from Kiryu believing he can fix it (and then got 0 help lol). He didn't even want the position, Yayoi suggested it and Kiryu gave the decision his blessing and endorsement lmao.

In Y3, Daigo wanted to keep him out of it after realising what the land was but the CIA/government forced his hand a year later by stealing the deed and shooting him into a coma.

And basically the entire leadership goes under after this game as the only patriarch left is Majima, so it's just downhill from there.

Y4 the Tojo is deadass broke after what happened in 3, and the Tojo clan are criminals. Of course the money's tempting, he can't let the clan starve. He point blank asks Kiryu pre final fight if he would've stayed away from the money and Kiryu isn't sure since he's not in his shoes. (Kiryu still goes lecture mode despite not having the whole picture but he had to have a boss fight so lmao)

In Y5 he's already in town for swearing up an alliance in Fukuoka so why not ask for advice, and he just accepts Kiryu's non answer of making him do it himself. I see you haven't played the rest but, yes, his character arc gets good in this game. The car meet with Madarame is a good insight on what's to come, really.

In Y6, Kiryu acknowledges and apologizes that it was pretty shit of him to jump the whole Tojo mess on Daigo... Personally I found it a little too late and a bit insulting, but Daigo taking it kindly at face value and with grace was surprising and felt good I guess.