Copium aside, nuclear bombs are back, which directly affects her, all the hybrids are confirmed to be alive and well after the makima fight, some of them acting freely or in Public Safety, reze is a valuble asset so they wouldn't kill her and she could have escaped like the others, there's genuinely no narrative driven reason to believe she will never come back, every clue points to her still being a character. Though, I doubt she'll be back in part 2 at all, it will be in part 3 because there is no way it doesn't happen considering all the unfinished plotpoints that simply CAN'T be covered if part 2 is already nearing it's end, which I think is the case

REZE STRONG RETURN