Welcome Svensonjr, what you have pictured is the PPQ .22 which has an internal hammer, is a full size pistol and has a sight attachment system that is different from the one on the P22.
The P22 has a cast zinc slide that is very, very thin on the top. It is too thin to have a dovetail machined into it. The firing pin runs against the underside of it. The rear sight is fitted over an integral cast, threaded loop. An adjustable for windage only rear polymer sight fits over the loop and is held in place and adjusted by a screw. This screw is snapped into a small receiver on the left side of the sight so that when the screw is turned it pushes or pulls the sight left or right depending on direction of the screw's rotation.
Yes, I did attach up to 43 grams of weight to the original style slide and the pistol still cycled reliably. There is a limit though, a .22 only generates so much blow back energy.
The reflex red dots are light enough for the P22 to cycle...attaching one to the slide is the problem. None are made that will slip over the loop for attachment with the screw. Neither is the zinc top of the slide strong enough or thick enough to be threaded for attachment of a base plate with screws. We have explored drilling through the slide and into the mim'd steel breech block but that is a tedious process. Glue has not been a permanent solution in attaching a red dot base to the top of the slide.
So, while a small red dot looks pretty good on a P22, we have not come up with a good way to attach one. There will have to be an entirely different method of mounting a red dot as there is no dovetail, nor any manner of adding one. Thanks for the photo. I could suggest how such a sight might be attached to the P22 slide but the mount would be unique to the P22 only.
The rear sight attachment loop. It is threaded and an integral part of the cast zinc slide. 1917