Concerns about my daughter's speech regression

I agree. Give her some nonverbal options. It sounds like so wants to connect with you and be heard and understood! Lots of autistic people like AAC or sign language to communicate.

What I hear is: she’s talking because she wants to communicate. That doesn’t mean it’s her preferred method and that she wouldn’t appreciate options. If whispering truly is her preferred form of communication: great, but we don’t know that yet. I would REALLY recommend working in nonverbal communication options for her.

So I have read alot of don't make her talk and I just want to understand. Because she talks and ALOT!! She is just below a whisper alot of the time and she gets SO upset when she can't be heard. So sane advice? I just what to do right by her and we are waiting to get in/o therapy.

If you scroll the autism posts here a little more there are lots of aymutidtics affirming the benefits of being nonverbal for their wellbeing and how they prefer to communicate

I would do everything you can to not push verbal communication. Let her speak if she wants to, but let it be a choice. There are many ways to communicate (such as AAC which was already mentioned). Putting the emphasis on communication (instead of just verbal communication) and adding nonverbal systems into her tool box will allow her to continue to grow and express her self in a way that works for her. It also may allow her to be mixed verbal (alternate between verbal and nonverbal depending on circumstances).

But absolutely I show her understanding when we struggle, not punishment, annoyance, or anything of rhe sorts.

If you haven't already, get her an AAC device so she still feels in control of her communication. If it's that upsetting, stop asking her to speak up and encourage her to use AAC instead. She may be regressing because she's going through something stressful you may or may not know about. If she goes to school, meet with her teachers to update them and work out a plan for how to make sure she still feels safe and comfortable at school. Regardless of how much she regresses, she's still your daughter and still deserves love and attention, not admonishment for not talking or not being "normal enough" or anything else that's ultimately out of her control. This is also important for her teachers to understand: regression is not a conscious choice and is completely out of her control. She's 7, she's not a grown adult who's acting out maliciously, she's just acting like an autistic kid

Or sounds like she's unsure of herself but I'm no expert in verbal communication in children with autism.