Good to see you, Abe.
Can't quite bring myself to claim being advanced, but I have been at it without a break for over 30 years, so wherever that puts me ... I play matched grip because I don't have to think about it, though traditional can be entertaining and I love watching other drummers use it.
I'd say my left hand can do about 75% of what my right is tasked with doing - and my right can probably do 90% of what my left is tasked with.
Equality between the two isn't one of my goals, though. They just do different things while serving the same master.
As long as they're competent at working together and I can pull off what I'm shootin' for ... if not, then I'll take the time to work it out. The way I prioritize my playing isn't to front-load the learning of skills; I learn what I need in order to play what I want to hear until I hit a wall and need to shed on a few things in order to hit the next idea.
I realize too, that this has more to do with my ADHD approach to most things, and I fully recognize the potential benefit to working toward more balance between the limbs. I just can't get exited about ritualistic practice routines when faking it until making it has its own rewards, and seems so much more in line with my personality type. Good thing I've never tried teaching!
As a drumset player, I'm hard pressed to imagine a situation where it would be terribly useful to get all that balance. Just the way a standard-ish kit is setup favors different roles for left and right sides. Only exception I can come up with would be someone like Mike Mangini, who really does use full ambidexterity in his playing - and has the setup to take full advantage of it - but it seems like a lot of work to get there, and perhaps limited musical application if most of what he's doing is simply mirroring. But it's probably a lot of fun if you have the time and patience for it.