Notice the Mark of Slayer on the floor of this space station. Hugo and Marty haclve mentioned the game having a "hub" area between missions. I think this is it. : r/Doom
Sentinel Prime might be the main hub for Doom Eternal - Doom Eternal - Doomworld
Doom Eternal 'Fortress of Doom' Hub Area Revealed
Doom Eternal - Wikipedia
DOOM Eternal Has A Hub Area, Here's What's In it
Doom Eternal: What is the Hub and where will it be?
Doom Eternal secrets: Fortress of Doom maps and locations guide - Polygon
Fortress of Doom (Doom Eternal) - The Doom Wiki at DoomWiki.org