Lost my iPhone
How do I log my account out of a iPhone I lost
iPhone 7 Plus
There is information in the following that may help: If your iPhone, iPad, or iPod touch is lost or stolen - Apple Support
I wouldn't recommend removing it from your account. See the following from the above link:
If you remove the device from your account after you erase it, Activation Lock will be turned off. This allows another person to turn on and use your device.