I'm concerned about wear (I know that the slide stop would probably round off before the slide and this is an irrational fear), but I just realized that an empty magazine is applying pressure upwards the entire time, correct?
The empty magazine's spring is lightly pressing the follower up against the slide stop and pushing it into the notch on the slide. Once the slide is closed, there is no movement. Even if you lock the slide open, and leave it that way, there's no movement! Generally speaking, metal has to be rubbing, not resting, for metal to be worn.
The only thing that might suffer wear in that second example (
i.e., slide locked open) is the recoil spring. And then only if the spring is very compressed when the slide is kept locked open for long periods (as in long-term storage.)
Some springs, depending on how they're used in the gun's design, can degrade more rapidly than expected if kept or regularly compressed to or near the spring's design (elastic) limits. (With some new designs, including some of the very small sub-compact guns, that can happen, by design!)
You don't have much to worry about.