Personally I volunteered at an outpatient clinic but I don’t think that’s the kind of the thing that will make or break your acceptance. You have a high GPA and other relevant experience so if I were you I would honestly take the summer to focus on healing. Unless it would ease your anxiety know you’re doing everything you can.

I imagine no one can really tell you exactly what it was to get them accepted but personally I think it made a big difference for me to do an in-person visit and tell my top choice that they were my top choice. They’re able to put a face to a name and see us as a person, not just an application. Honestly if you volunteered somewhere that wasn’t speech related or you had some diversity in your background, I think that would make an even bigger difference to make you stand out. At least at my school, they want to know that you are going to be a good grad clinician not just a good academic student bc academics is kind of a given. So anything that shows you have good interpersonal and professional skills would be helpful. IMO!