Who could have defeated Gerard?

I haven’t read CFYOW but is there not speculation that Hisagi and Shinji’s bankais may have been designed to counter Gerard and if Kubo hadn’t rushed the ending that might have been how he was beaten?

Wouldn’t be surprising. Lille and Pernida were beaten by lieutenants.
Yeah Hisagi’s bankai was tailor made to deal with someone like Gerard the original plan seemed to be that while fighting alongside Kenpachi and co from what I remember. Shinji was right there in the manga anyways, they could probably get him more involved in the anime but I’m not sure how effective his bankai would be considering how it doesn’t discriminate between allies and foes.
Hear me out. The power works on hope if I remember correctly. Have Mayuri make a drug that causes chronic depression, and then give it to someone like Ichigo, or Kenpachi. Wa-boom! No more Gerard.