Yes Matt. RBBF might be the very thing for you. Easy one-finger operation for the most part, but when you really need to hold focus for a while, that's just a thumb-press away.

I'm veering off-topic here, but since the topic was raised, I agree about the number of AF points. My EOS R has an AF point, for practical purposes, on every pixel. It sounds great, and sometimes it's handy, but it takes forever to select the one you want. Essentially, there are two methods:

(a) You can use the controller buttons. These are the four arrow-shaped buttons on the back of an R, essentially the same cruddy thing you used to get on an el-cheapo 400D more than a decade ago. They suck. The crippled-by-design R user interface uses buttons because there isn't room for a proper back wheel and a joystick. It is glacially slow. However, because there are a zillion AF points, a joystick wouldn't be a whole lot better.

(b) You can use the touch-screen. This is faster as you can just touch the screen on the spot you want. Alas, it has even more issues, and worse ones. First, it's rather inaccurate. Your finger is just too big to select the exact spot you want, so what you do is pick one roughly in the right area and re-compose to suit. (In other words, you do exactly the same thing you would have done on a camera with only 10 or 20 AF points.) Second, you have to have the screen facing outwards. This means your already poor battery life is suddenly a lot worse. And if you are left-eyed it is a horrorshow - your nose keeps resetting the focus point. Worst of all, you can't operate it without moving your hands and taking your eye away from the viewfinder. (And with a big lens you can't move your left hand.) Unless you want to use a camera held out in front of you like a tourist with a telephone, it's essentially inoperable.

Oh, and the AF points on the R are low-precision - in other words, they are way too large to use the way you use the precision points on a good modern SLR. (7D, 5D III and later, etc.)

The one good thing is that they cover pretty much the entire field of view. You can, for example, select a point in the lower left corner, which is sometimes very useful.

Actually, it would be quite simple to fix. All it needs is a mode where it offers a reduced number of selectable AF points via custom function, something like the number of points on a good SLR only spread out over the entire screen. (Good SLRs already do this for their lesser number of hardware AF points, have done for years.) Then, assuming a decent body design with proper controls, you can use the joystick (or, if desired, the touch screen) to select the point you want quickly and accurately, without having to move your hands or take your eye away from the viewfinder. Presumably, Canon will do exactly that when they get around to making a professional or semi-professional standard mirrorless model. (Unless they have completely lost the plot, of course. Their long history of excellent ergonomic SLR design provides evidence that they know how to do this stuff. Their existing two rushed and poorly-thought-out full frame mirrorless products (the R and the RP) suggests that they don't care anymore. Wait and see.)