Thanks, @robert

I found two plugins to resend the confirmation email

Tested this one and it only found one unconfirmed user, I don't know if the plugin is good enough, wonder why it didn't list all inactive users?

https://wordpress.org/plugins/unconfirmed/

Perhaps devs can add these feature in the future, seems not a complicated addon?

https://github.com/atwellpub/resend-welcome-email