which phones support Siri announcing notifications over device speaker?

Hello, all. I'm trying to determin exactly which devices support the new iOS 16 feature of having Siri announce notifications through the device's speaker. I've gotten it to work on my iPhone 13 pro without issue, but the option doesn't even appear to exist on my mom's iPhone 8 plus. The feature was available on my best friend's iPhone 10R, but when she enabled it, it didn't work. She was hoping to use it so that siri would read messages automatically while she was driving, but no matter what we did, it wouldn't activate for her. Does this feature only work on select devices, and if so, does anyone know which ones? Also, is it something that can only work if VO is active, or are there other settings my friend needs to look at before it will work? Thanks!