I'm doing a similar thing as
@Solius attempted, a full run of all Yakuza/Like a Dragon games, only I did Yakuza 0 first. I'm currently a good 20 hours into Kiwami.
For me personally, the trick is definitely to not play them consecutively. I finished Zero about 6 months ago, with 100-150 hours on the clock. Had I started Kiwami immediately after, I'm pretty sure I would've grown tired of it. In many ways it feels like playing the exact same game again. Still fun, but I do hope there's a bit more variety in the other titles.
At this pace it'll take me a number of years to get through the series though, so I might just do Kiwami 2 straight after this one, as this feels like it should be a lot shorther than Zero.