Network info

This is the iPhone forum, since you cannot even see network devices directly on an iPhone, there is no option to identify anything outside of using a dedicated 3rd party app that can scan your network. Wether the devices are known or unknown to you would not be something the app can tell you. But may be able to tell you what the device is.

Apps like Fing - Network Scanner for example.

See this Apple article: Check your Apple ID device list to see where you're signed in

Check your Apple ID device list to see where you're signed in - Apple Support

Remove the devices that is not yours.