Having the same problem since yesterday, version 12.1 (16B92),
Speaker icon is always grayed out when making calls or receiving calls, works good with Bluetooth devices.
Memo doesn't work, it says "No audio Device available" , when checking Sounds & Haptics the sounds is good.
All setting are good, phone came from Apple 3 weeks ago, no damage no water, phone is protected with Otterbox cover.
Reading on line it seems Apple is having a huge problem and they are not owning it.
What's good is a "smart phone" if you can't actually use it as a phone...it's main purpose.
Apple please help, and do not send us standing in long lines and wasting hours.