If you want to remove the strut to put a spacer on top then you probably *want* to loosen the KDSS screws 2-3 turns as it will make it much easier to get the strut out.
I had the dealer install a strut spacer for me as part of some other work including tire mounting and I'm pretty sure they did not open the KDSS valve as when I opened it a couple months later to put on a full lift the bluish marine grease I had slathered over the screws was still fully intact.
KDSS is a pressurized system. It's oversimplified but think of those 2 screws as separating 4 independent chambers. When you open them up the fluid can flow between any of the wheels easily. But they are set screws, so when you tighten them down they lock the fluid in place. If your rear end is on jack stands but the front is on the ground, the front will be compressed and will push fluid towards the rear. Then when you tighten them and set the vehicle back down the rear will have more pressure in it. That increases rear anti-sway bar stiffness but decreases the front. It also means as you compress a front wheel you would get less wheel travel in the rear than if the system were equalized. Now in the case of adding a 2" lift all around, there would be much less imbalance in the system so it should have minimal impact on handling.
In the description above the KDSS system is sealed and once you tighten the set screws you're done. But I've read that KDSS will naturally rebalance itself over time, and that some "cruiser lean" may be attributed to regularly parking on a non-flat surface (like a driveway at an angle) for long periods of time. I don't entirely understand how it works but I suspect that if the pressure is significantly different between chambers that a very small amount of fluid will "leak" between chambers over time, effectively rebalancing the system. Not sure if this is an intentional part of the design or just an artifact of a 600psi system with adjustment in it.