What's the firmware version of this plug which can't be deleted? I heard that old firmware has a bug which unable to unbind kasa account through reset.

Which step of configuration process did you stuck in?

Seemed like a compatibility problem, I found kasa has released Android v1.10.4, you can update and see if still exsit this problem. Hope they have fixed it.

Good suggestion, just contact tplink support team and let them know there are more than one demand such function.

What's the version of your Kasa? The latest for Android is v1.10.3. Also when create device name, you should make sure you have conneted to plug's wifi. And if you turn on VPN service on phone, shut...

No, one smart device only can be connected to one kasa account. For your issue, I think the only way to solve is to share kasa account as it can be logged in at the same time on several phones.