For an excellent explanation on how and why the solstice arrives on different dates for different places, check out these articles from Space.com:
https://www.space.com/summer-solstice-when-what
https://www.space.com/stargazing/summer-solstice-2025-brings-changing-seasons-to-earth-on-june-20
I spent the moment of the solstice itself gazing toward the horizon just as the sun was setting. Truly a spectacular sight.