How do I delete a display in the "add display" that I did not add?

thank you for responding. right click does not respond, left click, if you will, opens a small window with the message

"incoming connection blocked to living room" with the sound icon displayed with an "ok" box only. so, does this message have something to do with my firewall settings which in this can, is very good. am I correct in this?

next, how could someone else set up something for/on my device without my permission as to any settings?

thank you.

yes I know there are so many variables. I will try and explain more.

my own Mac mini is setup in my bedroom/sitting room with my Samsung smart tv as its display/monitor. yes there is another Mac mini belonging to my son in the living room. we do not have same logins or apple id's. we have internet service only from xfinity.

in sharing, I have nothing checked; I am guessing nothing is actually being shared due to the message I am receiving when clicking "living room." what else would appear if it was? I am very protective as to what I have and use and just do not understand how my own device and its information could even be setup/chosen arbritarly.

lastly, I am a senior citizen and things such as this are perplexing for me. thank you for your patience and hopefully, understanding.

thank you from one senior to another!