i have a desktop and 2 laptops.. they were in all.. they added their own remote.
Thieves use tools like Shodan.io to find vulnerabilities and exploit them.
I will second using Steve Gibson's ShieldsUp. Going to his site at https://www.grc.com will give you loads of security information.
Like I said: off line.
My computer at home is not connected to the internet or even a network.
I do internet on a tablet that does nothing important.