

Sounds like an amazing campaign, thank you for sharing 
The exhaustion / nimble dying rules sound like they would facilitate the “the Dieselpunk pulp fantasy vibes of Dishonored mixed with the socialist weird fiction vibes of Disco Elysium”
I totally get the charm of the roll for initiative and the randomness that d20 brings to the game both in the to hit and the initiative roll. If you are comfortable with the system that is just as valid as someone that changes systems frequently, having fun telling a story together is the most important thing to me.
Leaning into the exhaustion mechanic could be effective, spending more time investigation means you get more exhaustion. A fail forward consequence could be a level or two of exhaustion in addition to the usual HP loss / status effect / item loss.
Is there some sort of Dieselpunk way of removing exhaustion at the cost of HP?
How many of the players are full casters?
After having run many “tactical” systems I think it isn’t for me, I resonate with the approach you described and like the pie/meal analogy.
While you would need to tweak the setting a bit, The Between could be a great fit or Blades in the Dark. Especially BitD if you want to lean into the faction aspect, it is known for being a “heist” game but expanding on what the concept of a “heist” is can open it up to more robust campaigns.
Honestly though it sounds like you have a great idea for a game and using what works for you! Reminds me of some dimension 20 campaigns in the best way, and Eberron is such a cool setting








First thought was Andoran from Pathfinder’s Golarian worldsetting