Started Yakuza 0 this morning. Really great story set up and writing. I was expecting it to be super silly but it's actually really serious and I guess the quirky stuff balances that out later
The stories in these games are always serious (bar a few sections here and there), I was referring to the somewhat bonkers side stuff, which you're never forced to do much of. However, you'll lose a lot by not doing it and miss out on many hilarious scenes Without spoiling anything, this game is a lot bigger than you might initially expect and a lot of the content that can even reward you with new abilities/interesting stuff is purely optional.
Personally, I couldn't get through any of these games without diving into at least karaoke, Sega Arcade, fishing, completing substories and drinking/eating everything there is to eat
There's a lot more, including two very big substories with special rewards but you're rarely forced into anything