It is hard for me to see how a revolver would be easy to use for a person with diminished hand strength. It might be easier to load and unload by opening and closing the cylinder, but the double action pull will be a nightmare. Cocking the revolver might also be a big problem.
One option is the Beretta with the tip up barrel. This pistol never requires the slide to be racked. That said, the double action pull and even cocking it before you need it might also be difficult or impossible.
A semi automatic pistol without a recoil spring guide rod such as the 1911 will have a thumb safety, a grip safety, and the slide can be racked one-handed by pushing down on a hard surface. Once a round is in the chamber, simply put on the thumb safety. Then, all that is necessary to fire the weapon is to click off the safety and pull the relatively light four to five pound trigger.
There are plenty of videos showing many ways to rack the slide of a semi auto with one hand when the pistol has a recoil spring guide by using the sights, the red dot, etc. where you do not have to depend upon the weak hand to pull the slide to the rear.
To me, racking the slide is not really the problem. The problem to overcome is to be able to fire the gun when it is needed, and a relatively light trigger pull, four to six pounds seems easier than a 10 pound double action pull on a revolver. I think a person with arthritis would also have difficulty manipulating the hammer to cock the revolver fast when needed.
The vast majority of service autos these days are striker fired with light trigger pulls making them easy to use when needed. And, with one of the modern striker fired autos, the trigger pull is pretty easy. And, they are “set and forget.” Once loaded with a round in the chamber, all you have to do is pick it up and pull the trigger.