Michael-532 GrapheneOS randomizes the Mac address of the phone so the device can't be tracked by for example a public wifi.
But what if I connect my phone to the public wifi and share hotspot/usb-tethering to my laptop?
Could the wifi somehow see the mac address of my laptop?
Wi-Fi is made out of radios, and anybody with sufficient motivation can observe the MAC addresses of nearby devices. If the connection between the laptop and the phone is via a USB cable, and if the laptop's Wi-Fi interface is off, the public Wi-Fi access point won't learn the laptop's MAC address.