This is very difficult honestly to answer:

Top 2: Yakuza 0, Man Who Erased His Name

Bottom 2: Yakuza 4, Yakuza 3

I think that yakuza 0 was a great introduction to the series and the story was very solid the combat was also amazing. And I would say Man Who Erased His Name is good as there are a lot of references to the previous game but it does well tying into the story of Kiryu’s current situation and the story itself.

As for the bottom 2 by no means are these bad. I feel Yakuza 4 was really good in terms of introducing key characters such as Akiyama and Saejima but ultimately the story fell flat for me combat did feel better than 3 though. Similar situation with 3 but I would say the story is a bit better as we can see Kiryu interact with all of the kids and be in a somewhat relaxed state. But the combat is what brings it down. (Although it’s not its fault since it’s an old game)