Advice on making phone calls bearable for sensory processing issues?

I can barely function on a phone call. I don't know if it's overstimulation / overload or something else, but the feeling is extremely similar. Regardless, I need solutions

Facetime is better than regular calls because the audio quality is slightly better and we can actually see one another, but I have endless calls to make to doctors offices, which are not able to do video calls from the front desk. Most of these places don't even have an email box I can reach them at. My family also does not respect my sensory processing issues, and my mom in particular will call multiple times a day, which effectively locks me into that state.

Are there any ways to make phone calls bearable? Earbuds are no better than holding the phone up to my ear, and speaker phone makes the situation worse. The best I've figured out so far is having the phone on the lowest volume setting held an inch away from my head, but at that point i'm straining to actually hear the other person.