I've found pretty much any system that allows you to "compress" action resolution by allowing you to choose the level of detail you want for each scene. What do I mean by that?
- Feng Shui was great because it had "mook" rules, where the majority of opponents in fights could be taken out with a single success/failure roll of the dice. No hit points to track, no record keeping. The skill system was lightweight, and if you wanted a particular opponent to be a "boss" fight there was rules for that too.
- FATE Accelerated let you easily do things like treat groups of opponents as a single "stat block" to fight against, or in other types of scenes pick a "lead" character to make the rolls while still allowing the rest of the group to contribute bonuses and boosts to the result.
- HeroWars (now QuestWorlds https://www.chaosium.com/questworlds-system-reference-document/ ) let's you resolve the direction of entire scenes in a single dice roll.
This tends to be a feature of games that focus on more abstract, high level descriptive, mechanics rather than action by action resolution (which games like DnD or Hero tend to lean into more heavily) which may not be everyone's cup of tea... but they're definitely easier to keep flowing with bigger groups and all allow for longer term campaigns.
F# will give you discriminated unions and do-notation (it calls it 'computational expressions') while retaining full access to the .net ecosystem.