Thinking about the difference between becoming hard and becoming tough. Toughness is not incompatible with retaining softness.
And because I need an example, I'm going to talk about Arcane. Vi is tough, not hard. Vander likewise, that's probably where she got it from. Silco is hard -- he misunderstood softness and weakness and (mostly, not entirely) purged it from himself, and tried to teach Jinx to do the same. Ambessa is hard; she was fortunately unsuccessful at getting Mel to be the same, Mel is tough. However once she got her claws into Caitlyn Caitlyn started down that route (but did not complete it). I suspect Cassandra was tough.
And because I love my 2024 (Little Witch Academia) and 2023 (Willow (2022)) obsessions also...
Croix vs Diana. They parallel each other -- Croix chose to be hard, and failed to help Chariot; Diana kept her softness and chose toughness, and succeeded in helping Akko.
Kit at the end of the series has to make the choice, to be hard or to be tough. When she starts the series she has the two confused in her mind (though I suspect Madmartigan was very much on the tough side, not hard -- if anything its her mother thats harder). With Elora's encouragement, she chooses toughness.