iPhone speaker button shows other devices - Solution

Working for me, so sharing the findings if it works/help others.

1. On your iPhone, navigate to Settings > Phone > Calls on Other Devices.
2. Uncheck your Mac from the list of devices.
3. Next, toggle off the Allow Calls on Other Devices option.
4. Restart your iPhone to apply the changes.

Note: Simply turning off the "Allow Calls on Other Devices" option will not remove the Macs from the audio options list. To resolve this, ensure the option is turned on initially, uncheck all listed devices, and then toggle the option off. Changes to the audio options list may only reflect after restarting the device.