Sorry for the muddy list but I'm not entirely sure how many of the below are facts and how much is a figment of my imagination:
Platform(s): PC
Genre: Strategy/RPG
Estimated year of release: early 2020s
Graphics/art style: 2D/Western (no anime)
Notable characters: n/a
Notable gameplay mechanics: Story-rich, you needed to choose where you went on a map (choose your mission)
Other details: The game was about trying to stop a cult from summoning things and it was split into scenarios with different missions - once you did the scenario, you moved to another map. Every mission constituted a turn and it progressed the game (towards the summoning). It had some eldritch undertones and definitely was a Western fantasy style. If I remember correctly, it was pretty story rich and the missions resolved around your party being moved to a dungeon. I can vaguely remember that one mission revolved around rescuing a priestess? (Or killing her.)
I'm sorry, I know this is not much but it's been stuck in my head for a while and I have no idea what it might have been...