A brief anecdote: one of my dearest friends, a research scientist, only identified that she had ADHD-I midway through working on her doctorate. Until that time, her compensatory strategies had been sufficiently well-developed that she was able work without supports or interventions.
Your DD may not be able to articulate what change she’s perceiving, or she may not be comfortable doing so openly as she explores her feelings. What my friend described sounded quite akin to ambiguous loss, whereby she had to grieve the expectation she had held about her potential level of sustainable professional function. Your DD might benefit from some time with a therapist to unpack her intuition, even aside from the evaluations. It’s been a tough year for everyone.