Originally Posted by docbert

No. Whatsapp only supports WhatsApp->WhatsApp calls, they don't have way to receive/forward calls from a standard phone provider.

However you can do what you want. The Pixel 6 supports "Backup Calling", which allows one of your SIMs to make what is basically a Wifi Call over the other SIM. So get an eSIM for the country you're in, turn off roaming on the Google Fi SIM, and then turn on Backup Calling for that SIM. Any calls to/from the Google Fi number will route over the data connection for the eSIM, and basically be treated as a Wifi call by Fi (ie, no roaming charges).

Originally Posted by TGarza

It is baffling to me why more Android phones don’t support this option. iPhones have supported this type of calling for several years. At one time I carried a phone with a local sim with hotspot on to connect my domestic using WiFi. To me, this was a game changer when traveling internationally to use a roaming sim paired with my domestic sim.