Cannot select media or mediaopt for HotLava Tambora 40G2S ( Intel 82599)

I have a HotLava Tambora 40G2S card which is Intel 82599 chipset.

OpenBSD (7.2) detects this as ix:
ix0 at pci2 dev 0 function 0 "Intel 82599" rev 0x01, msix, 4 queues
ix1 at pci2 dev 0 function 1 "Intel 82599" rev 0x01, msix, 4 queues

However I cannot seem to control media or mediaopt ?

doas ifconfig ix1  mediaopt full-duplex   
and
doas ifconfig ix1  media 1000baseSX mediaopt full-duplex
both give
ifconfig: SIOCSIFMEDIA: Invalid argument

The interface is currently running in simplex, which obviously I'd like to change:
$ ifconfig ix1 media
ix1: flags=8843<UP,BROADCAST,RUNNING,SIMPLEX,MULTICAST> mtu 1500
        index 6 priority 0 llprio 3
        media: Ethernet autoselect (autoselect rxpause,txpause)
        status: active
        supported media:
                media autoselect

As you can see, "ifconfig ix1 media" shows only autosupported.

The transciever is a FlexOptix Singlemode MSA coded.

Rachel