FrogReaver
The most respectful and polite poster ever
Our games normally decouple skills and abilities. The player describes what their character does and how the character does it. This narrative description determines which ability and which skill proficiency apply, if any. The description might also modify the Difficulty Class rating. Some descriptions seem like they would automatically work, gain a bonus, transpire as a typical challenge, incur a disadvantage, or be virtually impossible.
That isn't decoupling skills and abilities. It's instead decoupling a single specific ability from a skill. You still have abilities coupled with skills, just not to a specific ability. I use that variant and it helps but not completely. If it could make a very persuasive fighter that's an amazing history buff and very good at fighting we might be onto something... I mean as cool as it is to mix and match stats and skills together, it really doesn't solve the problem that so many concepts are still unobtainable..
If 5e made it possible to use multiple abilities and multiple skills toward an endeavor, I would do it that way.
I'm not sure what this would look like?