Warhammer 40K: Gladius - Relics of War is a 4X game with a large emphasis on extermination because, as the saying goes, in the grim darkness of the far future, there is only war. Diplomacy is completely absent and the map is filled with aliens who exhibit different degrees of hostility. It's impossible to win by researching technology or hoarding art pieces either.
One would think that would make the game shallow, but not really. Combat is nearly omnipresent and matches are remarkably short for a 4X game so there's always something to do and factions have a lot of variety to them since it's a 40K game and there are tons of lore to draw inspiration from.
In terms of presentation Gladius is decent, the map kind of looks like a tabletop game even though it isn't based on the real Warhammer 40K tabletop at all. Sound design and animations are alright too, but I would like if there was more art in general, the menus and UI have a very bland utilitarian presentation in general and I sorta expect Warhammer stuff to have little skulls on everything.
My biggest issue with the game is the DLC model, you are constantly reminded of the factions and units you don't have yet and it gets annoying to bump into red tooltips reading "buy X DLC to unlock" in the technology tree. That stuff takes me out of the experience. At least the DLC is actual content for the game like new factions.
Overall, Gladius - Relics of War is pretty good for a 4X game, the factions are varied and fleshed out, the matches have little downtime and it's not yet another cashgrab licensed game.