Yup, these are tales as old as time. There are some darkly hilarious tales of rich rivals intentionally building tall structures to block their neighbor’s views, especially from the wild past in New York City.
Your only legitimate hope is a kindness campaign where you try to befriend the neighbor and figure out how attached they are to the trees. Tree trimming is expensive, and trees have a way of continually growing. The neighbor may not necessarily care about keeping the trees, but they also may not want to invest any sort of money to trim or remove them.
So yeah, if you can afford it and it’s worth it to you, you could offer to pay for trimming or removal. Otherwise you’re out of luck.