It's understandable to be sad. I know my own parents are and would love if we lived in the same country.
I moved to the UK from Australia when I was the same age "for two years", twenty years ago. Met my (British) now husband, had two kids and while we have always kept open the option of moving inertia is quite a powerful force and we're doing well, kids are doing well, and while I massively miss the Australian lifestyle and miss that my kids don't have what I had growing up, there are opportunities here that I never had so it's not a clear cut one way is better.
I am eternally grateful to my parents for never been anything but 100% supportive, never trying to make me feel guilty (I do feel guilt, especially as they get older but absolutely zero of that is coming from them) and for treating our relationship as a two way street.
I compare it to my PILs who, like some on this thread, have treated DH moving roughly 100 miles away as an active rejection of them and of his upbringing. It is a very one-way relationship, we have to initiate all contact and do all the visiting. We haven't had any family support from them over the years - the one time we asked (we were truly desperate) they declined to help.
I can honestly say my kids have a closer relationship with my parents and probably see more of their cousins on my side as on DH's. A lot of that is because we prioritise trips to Australia over all other holidays, my parents come here as much as they can, but it's also regular FaceTimes and Google chat messages with the kids, shared photos and chatty bits of news. It takes effort on both sides and it's not the same as being down the road but I'm so grateful to my parents for
how they've approached one of their kids living so far away.
DS1 is planning university in Australia so I know this is likely to be ahead of me as a parent - I'm hoping to follow the blueprint set by my parents.