mold and dead roots on the other one looks to be a goner but you seem to have more just go with the healthy ones otherwise unless it is some sort of golden cut you will just be in for a headache i have no problem culling when necessary it is part of the game
powder molds. Bugs . Plant disease . Roots damaged in soil ????? what medium are you in ?? Incorrect amount of nutrients or lack of . Ph ??? Idk what your feeding . To high no. To low yeah it can cause ugly leaves like im seeing . Are you under 4.0 ph ??? Many issues there . Do not start over your next plants will only get the same issues . Step one get a fan run it 24/7 for the mold . Step two tell us what your feeding and type of soil . And your water ph. Do not check soil ph .