Not caring about your extended family is normal.
Not everyone is close to their extended family, especially when the extended family live out of stat or far away and you have no obligation to call them, speak to them, visit them or hang out with them and you also have the right to not care about them.
You also have the right to not care about your own parents or siblings if they are not good to you.
Most of my extended family live way far away and yes they want us to travel 1,000 miles or more to visit them a few times a year but I'm not doing that.
They even offer to come visit me, but I really do not want them around even though they are not bad people.
I just hate hanging out with people I rarely see anyway and I also really have nothing to say to them as it would just be very awkward to have them over or even if me and my kids and and spouse would also visit them.
I barely am comfortable even being at close families houses, even when I see them more often.
I mainly sit around and sit in silence although if they say something I will talk, but it's hard for me to come up with any conversation unless someone else starts a conversation and so it's very awkward.