There is not a PPS model with a decocker switch, that I am aware of. As far as I know, the only variations are 9mm and fo-tay ... all the firing mechanisms are the same (unlike the P99)
The striker is pre-cocked, with some further cocking action accomplished with the trigger, and a reasonable trigger pull.
If you pull up the PPS manual (available
HERE)
... ...Go ahead, I'll wait while you open it up ... ...
you can see the striker mechanism on page 28, in fig 28.1, right behind/under lube point #4, there is a cruciform piece that pulls the striker back ... it mates up with the bit on the rear of the slide in fig 28.2 (right forward of the spring you can see in the cutout, which is, of course, the striker spring)
The striker is pre-cocked every time the slide moves rearward on the frame ~1/2", that cruciform bar (slightly better view in fig 13.1 & 13.2) pulls the striker back a bit and then drops out of the way, releasing the striker and firing.
So, the bottom line is that the action is not quite "double-action only", but not "single-action" either, hence the "pre-cocked striker fire" name, which makes sense only if you look at the internals.
The end result is a medium-weight trigger that after some break-in is very smooth and comfortable, with a good reset length for follow-up shots. It is NOT a target/match trigger, and it was never meant to be, but it IS a great SD pistol, and still more accurate than most shooters.
Oh, I figured out the "decocker" bit ... the PPS has a detachable backstrap that doubles as an interlock to disable the gun, much like a magazine interlock ... pulling the backstrap will decock the gun, but as there is no way to pre-cock the striker other than moving the slide, de-cocked carry is not a very wise option. The backstrap disabling device is for storage or shipping, and of dubious value otherwise ... I figured out which backstrap was comfortable and haven't removed it since, for disassembly I simply dry-fire like a Glock take-down, rather than pulling the BS.
I see no real improvement over removing the slide or barrel from the gun, so I leave it alone, but ignore any worries about dropping/breaking the backstrap during a reload, I tried to pop it out with a mag, and it took serious effort and actually looking at the mechanism ... it is not a concern during a reload.