Sucks to hear that the PS Plus retro catalog is so limited, but hey, at least you got all of the PS4's new and shiny games available at hand!
I had only played with a PS4 two times: One at a friend's house that had borrowed a PS4 from someone else (and had Fortnite in it, but only could play like a minute before the internet got disconnected), and another time with someone who used to have a PS4 and Mortal Kombat X in it. I remember being quite impressed with how fast it played compared to MK9, and was definitely fun to try out.
I played X near completion on my PC and will probably do the same with 11 now on the PS4.
Going back to X feels awkward now lol