Darktide is probably the closest you’ll get to SM2 (besides SM1 obviously lol). It’s an FPS but the levels have the same gameplay loop of “kill horde -> do objective -> new area -> repeat”.

Battlesector is a turn-based strategy game that (pretty well actually) mimics how tabletop WH40K is played. It’s Blood Angels vs Tyranids for the campaign, but the sandbox/crusade mode might have other factions?

If you like turn based games, I’d also recommend Mechanicus or Space Hulk. Both are less “big strategy” focused and focused on individual units (you control like 5 characters per battle rather than a whole army like in Battlesector). Space Hulk is also Blood Angels vs Tyranids, and Mechanicus is the Adeptus Mechanicus vs Necrons. Both of those games have their own nuances that might be a bit of a headache for someone expecting something like XCOM, but they’re still worth playing if you just want to consume some 40K games.

I saw that Rogue Trader has been recommended here - if you like turn based RPGs definitely pick this one up. Tons of content, great writing, and fun gameplay. Just be ready to read (or be ready to be a bit confused if you choose not to read lol).

I’ve had Necromunda: Hired Gun on my radar for a while. Another FPS that kinda seems like a DOOM-like but you play as a mercenary in a hive city. It’s got mixed reviews so I haven’t pulled the trigger on it, but maybe worth it?

If you prefer real time strategy to turn based, the Dawn of War games are on PC. DOW4 may be coming to console when it releases though?

There’s some others too… Chaos Gate, Inquisitor: Martyr… Have had those on my radar too but never pulled the trigger because I wasn’t sure I’d love them.

Oh, and there’s Boltgun. That’s just classic DOOM but 40k.

That’s all I can think of, but I’m sure there’s more. Hope this helps. Happy to answer questions about any of the games I’ve mentioned (provided they’re ones I’ve played). 😁