My son would understand that type of behaviour is wrong, I’m getting the sense her dd does as well.
I get what you're saying, but IME (as an autistic person and carer of three autistic young adults) it doesn't matter what you know to be correct behaviour or what the rules are in that moment if you're so overwhelmed with anxiety or stress that your executive dysfunction is out of the window and you're having a full-blown meltdown.
There's always regret later and autistic teens and adults who have meltdowns don't lash out because they've decided to - it's that all rationality has temporarily left the building. My DC break their own beloved possessions during meltdowns - they are intelligent, rational people much of the time (well two of them are, at least!) but when they're overwhelmed/sleep deprived/unwell/hormonal, then what they want to do and what they actually end up doing aren't always aligned.
There's a lot that can be done to minimise the occurrence of meltdowns, but part of that might be removing some of the demands that the person is finding too difficult to cope with at present (like working, or getting rejected from your dream career, if those things were part of the problem for OP's DD), or approaching the demands in a different way (e.g. supported internship, asking for reasonable adjustments to the recruitment process under the EA2010 to accommodate some of the challenges, if relevant, etc).
It can be hard for parents of autistic teens transitioning into adulthood to keep up with their DC's needs as the demands on them change so rapidly in those late teen years that it can be really challenging for parents to work out what their DC is actually struggling with out on their own and what, if any, additional support they might still need.
Plus, there can be a lot of shame for young autistic adults around admitting you're struggling with things that other people seem to be able to do effortlessly (like following instructions, dealing with customers, trying to use initiative when your brain works slightly differently from what's expected so your idea of what might be helpful is the complete opposite of what your boss finds helpful, etc).
It's really tough, and I know I've struggled massively at times to adapt quickly enough to my DC's evolving needs.