The ARPG WH40K Inquisitor - Martyr is unironically pretty good in its' genre. All the live service seasons are accessible on character creation now, individually, and in offline mode. Pretty solid endgame, combat flow and selectable difficulty are different enough from PoE and Diablo to provide some unique gamer moments.
As a big fan of Helldivers, they aren't really that similar. They aren't completely different either, but SM leans closer to a hack n' slash. Definitely space for both in my rotation.
The games that most directly capture the feeling are more difficult to make and balance for fun. The more factions that are playable the more effort it takes to keep everything balanced, which even the tabletop game has always had issues with. The more successful games tend to capture the themes and do their own gameplay.