I never have and don’t ever plan too. One thing I won’t step foot on an airplane but also I have no interest in traveling by air or anywhere outside of the US. I do want to at least visit 48/50 states though so far I’ve visited I think 17 states. They gave us the option to go to Paris, Rome and somewhere else in high school but hardly anyone went and I would never go anyway. I’m perfectly fine with staying in the US and traveling by car or I’ll do trains but nothing else.
I’ve never understood the appeal of wanting to go outside the US. If I went somewhere outside the US I probably couldn’t get fast food as easy meaning I’d starve on the trip because I don’t eat anything else when I travel.
I truly wish you would change your mind, however I completely understand your sentiment as I was the same growing up in a non-traveling (except for driving trips) family and a father that would not get on an airliner and had a bit of the "..'nough to see in the US" opinion. That is how I grew up.
Then I started traveling, truly traveling as in I filled a passport and then some. Mosty with work, when I would add in a day or two or a side-trip whenever I could but also pleasure. I did get to a point where the last place I wanted to be was on an airliner, but that took a long time

, and that feeling passed.
Meeting locals, learning their culture, history and
perspective, eating
their junk food. Seeing the sunset from the Eiffel Tower, a live volcano off Japan, forests of Bavaria, WWII relics all over Europe, fleeing a crowd of young men with bottlles and sticks from a dead end*, in reverse, in a 3 cyl rental in Johor Bahru (couple wrong turns...laugh now, but this was bad)........all valuable experiences.
Went to a Subway in Dubai, unusual for me but I just needed to eat something before a meeting. A local businessman wearing a thobe was walking there at the same time, smiled and waved me to go first than said "..six thousand miles to eat here?".
Others have stated the benefits of travel better than I can, so I will not repeat but I will leave one thought; You won't know, can't know how enjoyable or valuable the experience is until you've done it.
*"You American? You lost, you lost!! You come here.....you come NOW!"