That the bluetooth calling functionality that we had on the 5.1 watches didn’t make it to the 7.1 watches isn’t because of Googles security policy, but rather because it has been difficult to make for these watches
But, since you say that the c8 chip is already used in some headsets, it could be that it would be easier to get bluetooth calling working on that chip instead of on the regular chip. It might also be difficult to get the c8 chip to work together with android(or maybe its easy, idk). maybe they could make bluetooth calling available, but only in low power mode
As for the changes in googles policy, they made it so that watchdroid couldn’t show notifications for incoming calls or messages any longer. Using the c8 chip wouldn’t help for watchdroid as the policy restricts the app on the phone from requesting access to the call and message information(as long as the app is published on the play store)