The two you already have are pretty much endgame quality and I can't imagine the same knife in a different super steel would really scratch the itch. For me at least, I don't get as good a buzz from buying duplicates. I'd suggest a Manix 2 Salt LW in magnacut (or the g10 flavor comes in just about any steel you could imagine), a Shaman, Military 2, Native 5, or Endura 4.
I've been carrying the PM2 as my main knife since it came out in 2010, so I completely understand your mindset. I like it so much that I didn't buy another folder until 2021, which was an Endura 4. It's a wonderful knife, and I abuse and disrespect it (lol) in ways that I'd never treat my Para. I cut wires, really thick zipties where I need to pound the spine of the knife to make the cut, and I deburr copper and aluminum after machining or drilling holes. The edge has some chips that I don't bother sharpening out because I'm just going to chip it again. It's really nice to have a beater.
Anyway, to answer your original question, for your next PM2 check out 15V, Magnacut, K390, or M4.