There have been a lot of greatposts noting the similarities between Chara and Undyne’s personalities (concerning their anti-human and hero/hope of monsters complex) But not many people have seen the similar struggle with self-image both Chara and Dr. Alphys share?
Chara’s hatred of humanity and how they coped with they themselves being a human (the enemy of monsters) Dr. Alphys being the Royal Scientist, but having to deal with the repercussions of the failed DT experiments. How both struggled with the responsibility of their positions: Chara as the Hope of the future of monsters and humans and Alphys as the one charged with unlocking the power of the Soul to set monster’s free (without having to rely on waiting for another human to fall)
The buttercup incident could have been for Chara what the Determination experiments were for Alphys: A proof of their failure at their station and at being a good person.
Remember that Chara only mentions their plan to free monsters after that event. Remember that Chara was a child who, while they loved gardening, didn’t know everything about plants? Remember that Chara’s plan involved their suicide, through poisoning themselves the same way they poisoned Asgoere aka Mr. Dad Guy!
What if during their time living happily with the Dremurrs, Chara had been scared of themselves and their “human nature”?
Alphys herself at the True Lab will say that she was afraid she would do something “cowardly” (And in some of the really bad neutral endings she “disappears”)
Both characters carried the burden of bringing hope/saving an entire population. Both characters made a mistake that almost cost someone else’s life. Both characters contemplated suicide (one with through with it, and for the other it’s a possible ending)
Chara’s attempt to make things right ended in further tragedy. With help, Alphys was able to accept their faults and move forward.
((And with Frisk’s help Chara can move on as well))