As far as I've seen there's no solution aside from ADB and custom coding to preform call forwarding over USB that can be trusted; BlueTooth self induced MiTM I don't consider very secure for client calls ... side note here, "Bad USB" (AKA Rubber Ducky or HID) attacks are to easy to deploy if your device is infected with the latest generation of cross platform malware; if one cares about their workplace security phones shouldn't be plugged into the corporate network or computers... so I'll suggest what I know to have worked for providing similar features you've requested.

The trick I've used in the past doesn't require the phone to be connected to a PC to answer calls but should still work as desired; look up Google Voice number to forward calls to your cell or PC; additional benefit of using Google Voice is that groups of contacts or individual contacts can have their own custom voice mail greetings setup.

As far as I've seen, there's no solution aside from ADB and custom coding to perform call forwarding over USB that can be trusted; Bluetooth self-induced MitM, I don't consider it very secure for client calls. Side note here, "Bad USB" (AKA Rubber Ducky or HID) attacks are too easy to deploy if your device is infected with the latest generation of cross-platform malware; if one cares about their workplace security, phones shouldn't be plugged into the corporate network or computers. So, I'll suggest what I know to have worked for providing similar features you've requested.

The trick I've used in the past doesn't require the phone to be connected to a PC to answer calls but should still work as desired; look up Google Voice number to forward calls to your cell or PC; an additional benefit of using Google Voice is that groups of contacts or individual contacts can have their own custom voice mail greetings setup.