There are plenty of pistols thumb safety lever that simply do not work for me. Some are on the frame, and, some are on the slide.
There are two safety lever systems that I do know work for me. (There may be others.) One is the original-sized 1911 pistol, and the other is S&W DA auto pistols, through the Third Generation. Each is ready to fire when the lever is aligned with the target. For me, at least, up-or-down is not as important as the final orientation of the safety lever, when it is ready to “Fire.” A similar motion, with my thumb, will off-safe either weapon, though they move in different directions. Of course, in the case of the 1911, my thumb remains on the top of the lever, while ready to fire.
A miniaturized 1911, such as the Colt Mustang, or the SIG copies, do not work for me, as the safety lever is too far to the rear, requiring me to break my firing grip to manipulate the lever. I have handled other auto-pistols, with safety levers that did not work for me, for various reasons. I have generally avoided buying such weapons.
The semi-auto AR15 selector lever has caused cognitive dissonance, for me, as the position for semi-auto “Fire” is downward. This is one of the reasons I stopped being one of my employer’s patrol rifle units; the AR15 selector was not my cup of tea. (Another reason was because the rifles had to stay cased, in the trunk, except during narrowly-defined circumstances, whereas my shotgun could ride up front, with me, could be in my hands, at my discretion, and I could use buck or slugs, at my discretion.)