Yubikey authentication in RH8

Good morning.

I am in a project where we want to use a Yubikey like second factor to authenticate the users in RH.
We have a closed network (without internet connection) with several RHs (clients) that authenticate users against a RH server with an OpenLDAP. We are using the gnome version.
In that way, we tried to use the OTP mode of yubikeys, but we need access to Internet to send and receive requests from an API.
Later we tried to use the challenge-responde mode, but is only valid for local users (not users located in an openLDAP).

How can use Yubikeys in our project?

Thanks and regards.