IP ADDRESSES

Are the IPV 4 and IPV6 addresses under System Preference and TCP/IP on my IMAC private or public addresses? The IPV4 address under system preferences does not match my IP address found on an internet search. But, the IPV 6 does. The reason I ask is I tried to sign in to my Malwarebytes account and was denied as my IPV 4 address changed. The  IPV 4 address noted by malwarebytes is seen on an internet search for my IP address. I was trying to contact Malwarebytes as I have had a lot of spam and on 3/8/22 I received a text message from Comcast alerting me that an iphone just connected to my home network for the first time. This message was quickly followed by a text message stating that an ipad also connected to my home network for the first time. I have no new equipment so I changed all my passwords. 3/29 I called Apple about the IP problem, he said it is a Comcast issue. Today I called Comcast and was told Comcast never changes IP address and that I control the IP address. She said to call Apple and ask them to release and renew the IP address of my email (I did tell her that I use Comcast mail, not Apple mail). All I want to know: (1) is the change in the IPV 4 address valid? Was it done by CC? (2) IF the IPV 4 and 6 addresses found under system preferences are private,  why is the IPV 6 found on the internet search? I am very confused.