Hi,
I think this is rpm you need:-
http://linux1.fnal.gov/linux/elrepo/dud/el9/x86_64/dd-be2net-12.0.0.0-15.el9_4.elrepo.iso
(Sorry initially linked the wrong version for point release, thanks to leteaa & jlehtone for providing the correct version).
Someone else had a similar issue with a gen7 and a rocky8 (Although in there case they were trying to install the wrong version of the rpm initially). HP proliant bl460c gen7 - network interface - rocky 8.5
The easiest way would be to probably create iso containing the rpm. If you then install Rocky using the minimal or dvd iso. After the OS is booted attach the iso via the console in the ilo and install the rpm dnf.
Regards Tom.