A bit late to add, but someone in Valrak's discord pointed this out to me. It would appear this design is a Defiant class, although if @CALiGeR_Reborn wants to make sure I've got that right it would be appreciated.
From my memory the Defiant is one of the vessels from the Imperium with the alternative prow design, common in Battlefleet... Callexus? I think. Again I'm going off of memory that is quite old so correct me if I'm wrong.
Regardless, this vessel is a step away from the Gothic Sector vessels we see and a hint that perhaps we will be getting more of the Imperial vessels available to players.
^The Defiant class for reference