We are getting somewhere, just maybe not where you want to be.
Hah, well I meant that it seemed like you and I were coming to something we could agree on.
The idea of allowing expertise to match your better contribution from proficiency or ability isn't making the classes worse IMO, it is bringing them back within bounded accuracy.
Not meaning to sound like a jerk here, I promise, but it's not really a matter of opinion: You're effectively taking away certain options for rogues and bards (taking expertise in stealth or persuasion, for example), and making expertise worse in any skill associated with an ability where they have a positive modifier, without affecting the other classes at all (in fact, if you couple that with increasing the proficiency bonus across the board it's a double whammy to the rogue and bard). If you think those classes are too strong and need nerfing, that's an opinion, but the fact that this rule in isolation makes them worse is just objective fact (unless you think the ability to take an 8 in a stat and get expertise in an associated skill without suffering the -1 is worth a tremendous amount, but I'm pretty sure that's not where you're coming from).
Now, if you're not doing this in isolation, maybe you can make up for it. You already described some nice additional cunning action options, which is something. But bonus actions are only relevant in combat or combat-like settings, andfor me at least, a big part of the reason to play a rogue is to excel in some parts of the other pillars. So I would feel better about the change if you were offsetting the nerf to expertise with something else to those classes that would benefit them out of combat.
Even with 2d10, the same issue remains that (for only the sake of a class feature), rogues and bards have the potential to be better at things than other classes which would naturally excel at those skills.
They sure do! That's part of their class identity!
Or maybe just cap the total modifier for RAW at +13 or so, regardless of how you got there. It will require more thought...
Again, the only classes that can exceed that RAW are rogues and bards, so this change would weaken those classes relative to the others.
The bottom line for me is that I think there are ways to address the problems you perceive exist with expertise that don't single out skill monkey classes, or at least narrowly address certain edge cases. For example, changing the way passive perception works across the board, treating natural 1s as automatic failures on skill checks, restricting expertise to class skills, finding some class-neutral tweaks to a 2d10 skill system, etc.