How do I lower iPad volume of voice calls, (phone, zoom, bluejeans etc.)

iPad has had a few sound quirks over the generations. The current control center has really helped consolidate the variables, although I still think it's weird to relegate alert volume to the settings. But this has nothing to do with any of that.

I sometimes use my iPad to take and make calls. It's actually a fantastic interface while multitasking at my desk. But the volume seems to operate on a separate circuit; it can't be controlled with the standard media volume in the control center (or buttons) and it can't be controlled using the alert volume in settings. It seems to be locked in 100% volume, both through the iPad speakers, and when using airpods. It actually hurts the ears.

Is this a bug, a glitch on my device, or is there a setting I haven't found?