AppleScript App to start a Slideshow in Finder

I want to write an AppleScript App that starts a full screen slideshow with all pictures in the currently active folder in Finder (on Big Sur/Apple M1). Manually, in Finder I would have to open a folder, press command ⌘+ A to select all pictures (or files) inside, then press option ⌥+ spacebar to start the slideshow. I want to write a Script-App, that does all that for me (and which I then can put in Finder's toolbar). I am a newbie to this all, so please explain it for the dummy I am!