Pedantic
Legend
I'm using illusionism here to criticize the idea players should not know the rules of the game they are playing. It sounds like you're proposing that TTRPGs with less rules provide a greater sense of immersion, which I'm not totally sure interacts with my proposed definition.This. I'm only immersed(and it's not illusionism no matter what @Pedantic says) when I'm inhabiting my character and acting as he would. Sometimes I forget I'm playing a game, usually it's there but in the background. What pulls me out of immersion are rules and dice. If I have to stop to roll dice or use a rule for something, I'm automatically no longer immersed in my character and back out as a player, so rules that simply match what I'm doing as my PC fail to provide immersion if I have to refer to them or roll anything.
The best immersion comes during roleplaying interactions where I'm not rolling much in the way of dice, or exploration where dice aren't used often. Combats, being very dice and rule heaving D&D make immersion impossible.
It would all come down to how you are resolving conflicts in the shared fiction. If everyone generally agrees about character capabilities then you might never actually need to roll out a resolution mechanic other than the default "collectively decide what happens" and no one will ever encounter dissonance, which I would absolutely agree is an immersive state of affairs. I'm generally skeptical that such a state can be maintained by adults in an open-ended roleplaying situation, especially one that focuses on combat, and especially when you're in a fantasy or sci-fi or other setting that deviates significantly from normally experienced reality.
I think we're just quibbling over how much information about risk is necessary. I think D&D's 5% increments are about as fine-grained as I'd want software running on my brain to go, and I could probably be comfortably with a 10% standard, but I would side-eye anyone who didn't evaluate a 70% and an 80% chance of success differently. After that, we're just asking about which adjectives should indicate which DCs, and I generally think that's improved by putting them down in manuals.You don't need to know that success is 78% to make a good, informed decision and have agency, though. You just need to know that it's more likely than not, but with a decent chance for failure. That much should be evident to you by the situation, assuming the DM has described the environment correctly.