Any books like Legs That Won't Walk

not really mafias but close and the feel is similar
https://www.mangago.me/read-manga/enthusiasm/

this one looks good to more on the mafia side
https://www.mangago.me/read-manga/shutline/

and this one
https://www.mangago.me/read-manga/under_the_green_light/

You might have already read this, but Saezuru has a strong yakuza plot line https://www.mangago.me/read-manga/saezuru_tori_wa_habatakanai/

I haven’t tyy

I read that it’s so good

this series is pretty good tho it is a Japanese manga and not a webtoon i listed it in its order

https://www.mangago.me/read-manga/bi_no_isu/

https://www.mangago.me/read-manga/kobi_no_kyoujin/

https://www.mangago.me/read-manga/bi_no_kyoujin_smoke/

Tyy