New iPhone 17 Phone Calls with Bluetooth sound VERY sharp and harsh.

I think you’re mistaken. Both Zoom and Teams use VOIP for voice primarily. Teams is almost all VoIP if it’s used within an office setting. Outside calls dial in and then becomes an office VoIP call.

Zoom I’m not as familiar with but I suspect works similarly. Both list VoIP as their primary method.

If you force a cellular connection and you use one of your headsets does the issue exist? Say you call a friend or spouse, do you get the sharpness like you do with Teams?

I’m experiencing the EXACT same thing and I’ve tried everything you have, including exchanging for a brand new device and having Verizon reprovision my line. I have multiple Bluetooth headsets including AirPods and two high-end Poly models used for work. They’re fine with my iPhone 14 Pro, Teams and Zoom. The problem is only with voice calls on the 17. Music and videos sound fine. I’ve spoken with a post-sale manager twice and they indicated they weren’t aware of any widespread issues but didn’t deny it could be software-related. Their advice was to exchange the phone again to see if anything improves, but that’s a hassle and I’m not convinced it will solve the issue. I’m hoping this is a HFP codec issue and Apple releases an iOS update to resolve it.

Your voice calls, are they over cellular network or VOIP which apps like WhatsApp and many other third party apps use.?

My voice call are over cellular