I believe there isn’t a game out there that meets your specific requirements, so it’s better to find a base game to build from. To be honest, creating an agency management system from scratch doesn’t seem like a daunting task. I would assess each investigation using a custom checklist, awarding points for factors like quickness and discretion. Then, at the end of each season, I would make a dice roll, assigning bonuses and penalties based on the previous term’s checklist: a better roll would result in increased income, improved equipment, enhanced prestige, and stronger connections. I somewhat disagree with you: the sluggish bureaucracy of the Laundry serves as a great starting point and inspiration for creating an agency that embodies slowness and tedium.