Progression systems I have liked (as well as how they handle drip content, cosmetics, DLC, and, microtransactions):
DRG
HD1 and 2
Remnant 1 and 2
Roboquest
Void Crew
Satisfactory
Factorio
Gunfire Reborn
Killing Floor 2
Necropolis
VT2
(Not really the same genre)
BG3
Batman Arkham Games
Shadow of War/Mordor
Control
Cult of the Lamb
Dark Messiah: Might and Magic
Disco Elysium
HardSpace: Shipbreaker
Horizon Zero Dawn
Legacy of Kain series
Mad Max
Mass effect series
Mindustry
Miasma Chronicles
Overlord 1 and 2
Thinking about it for games similar to Darktide and taking into account premium cosmetics and content I feel like DRG is probably my favourite of co-op shooters. Even though DRG isn’t my favourite by any stretch. It’s fun.
If I could have DRG’s itemization, cosmetic, and season content and how they handle DLC married with Darktides graphics, combat, and talent tree… that would be the best. Overclocks for melee and ranged weapons would be so much more interesting than blessings.
It really doesn’t take much to have a mediocre system. Don’t have to break the mold, there’s a reason so many of the ones I listed are pretty similar and why they’re so common.