I chatted with Apple Support and they said I will need to send in the phone for physical inspection. Then my son showed me that one reason the mics and speakers may not work is if there is a problem with the battery. Look at your battery settings - my iPhone 7 said the battery was significantly degraded and in need of replacement, and could not support normal phone function. I switched to a newer iPhone 7 with good battery and it works fine (with the new iOS 15.5 update too). A new battery for iPhone 7 is $49 from apple, can likely get for cheaper after market. CHECK YOUR BATTERY in Settings - if it is degraded, that is likely what happened; will need a new battery to support this new update.