Plain Escape from Tarkov raids (SPT, offline single player) with Warhammer 40,000: Space Marine 2 as your soundtrack and your squad.
Battle music that swells. When shots ring out near you, Space Marine 2's Imperium combat music kicks in with a riser, then builds from its low to medium to high layers as the fight heats up (kills, hits, sustained fire), with a swell into the heaviest part. When it has been quiet for about 20 seconds it ends with an outro.
A squad on the vox. Titus and his two battle-brothers react in their own voices when you drop in, when a fight starts, when you kill someone, take hits, get badly hurt, pick up loot and start extracting. Extract and you get Space Marine 2's victory sting; die and you get its defeat sting.
From your own copy. All music and voices are read from your installed Space Marine 2 while you play. Nothing from either game ships with the mod.
Solo. Music and voice volumes are in the in-game mod settings (F12).
Needs: Escape from Tarkov through SPT 4.1, and Warhammer 40,000: Space Marine 2 installed.
Credits: music and voices by Saber Interactive / Focus Entertainment (Space Marine 2, read from your install); Escape from Tarkov by Battlestate Games; SPT by the SPT / Single Player Tushonka team; audio decoding by vgmstream (bundled with its license).