Pubg standalone may not have been first, but in its mod form for arma i think it was the first. Someone less lazy can probably look up the specific dates

Super Bomberman from the SNES already had the concept of a looting, survival multiplayer game in a shrinking map.

There's nothing new under the sun.

If you keep pointing at technicalities you're going to find that not much of anything is original or a new idea. I think PUBG gets the credit.