How to change wifi device name on Android 7?
AFAIK it's possible that a phone manufacturer hide that option from UI on their products, and I guess your phone it's one of them. My phone OnePlus 5, however, does allow changing it from Settings app.

So, if root access is available, try this in a rooted terminal environment:

setprop net.hostname "Whatever You Like"


Mount /system partition as R/W, head for /system/build.prop. Find this line and if it exists, change it (this line may not be present on Android 5 or lower):

ro.display.series=Same As Above


Reboot is required. After that the new name should have effect. Before modifying build.prop consider making a backup of it (and have a means of restore, e.g. via recovery-mode): if the file is "broken", your device won't boot up properly.