I think it was three letters.
The plot was about people that are thrown into an experiment with two gamelike traits, if one is good then the other is detrimental. The are only able to see one of the traits of the other participants. When the MC dies he is goes back to the start, but almost everything changes even his traits (people he meets, monsters he fights ...) and the game gets harder. The theme is a bit dark and the way the game is presented its easier to kill each other, our MC doesn't know if he's the only one to go back nor why or where he's trapped .

So the start of the series is that he dies again and gets the traits of being able to have unlimited passives, but a maximum of 2 active abilities. So decides he'll try to get to the end of whatever he's in.

L.A.G

~4400 manga completed
~1700 ongoing...

Yes that's the one thanks.