The streets here in my town have little rises at the drive through intersections and my CX5 is constantly quickly shifting from 4-2-4. Uggg
That may not be cylinder deactivation per se. If you approach the bump with a foot on the brake or while coasting, you're not shifting 4-2-4. It would be 4-0-4 or 2-0-4, where the 0 is not cylinder deactivation--all pistons are in motion with little or no fuel being injected as is typical with fuel injected engines when the foot is off the gas and vehicle in motion.
If you keep an eye on the real time mpg meter or the cylinder activation display on the screen you should find that 2 cylinder operation occurs under constant light low load with steady pressure on the gas. The real time MPG meter at around the 50-60 range is indicative of CD in operation. If the needle buries at the high end (80 MPG in my vehicle, some say theirs is 100 MPG), that's the 0 cylinder mode.
Now it's possible you might go 2-4 if you approach the bump at the low load constant speed to be in 2-cylinder mode and then accelerate after crossing but you'd have to monitor your behavior in conjunction with the displays.
Further, my skepticism is reinforced by my observations that less than smooth shifting typically does not involve 2 cylinder operation. Slight, brief lugs or jolts occur for me in the first to third gear range when easing off the gas or braking and then reaccelerating where the 2 cylinder sweet spot does not come into play.
Now, while the less than smooth shifting might not be cylinders deactivating per se, it could be systemic encompassing engine, torque converter and transmission control compromises to accommodate CD. That might seem like splitting hairs but when you consider it situationally, whether the vehicle is or was in two cylinder mode, there's some useful information to be gleaned.
Even so, one of the most technically knowledgeable people in this forum has reported lugging when making U turns, a deceleration-reacceleration scenario cropping up in his 2017 pre-CD, so there's more going on that just CD. Frankly, I'm very surprised the term "lugging" almost never comes up in these discussions.
Experiences will vary based on versions of engine, torque converter and trans control software. You'd also have to parse the differences in reports between FWD and AWD. But one thing should be constant--2 cylinder operation is in that low load, steady gas pedal pressure scenario. It's why many report across years that sport mode alleviates the issues--it revs higher and is less prone to finding the 2 cylinder sweet spot at low load and relatively low constant RPMs.
Is my experience terrible? No, it's an occasional annoyance mostly in lollygagging situations. If you have to slog through stop and go rush hour traffic it might rise above the mere annoyance level. A 150 mile back road trip with travel through a few villages presented no annoyances. Beats some janky raspy CVT. However I do wonder if those minor jolts put undo wear on the trans.