Need advice on pruning arbor vitae and hornbeam.

The hornbeam in my front yard has become so dense and the arborvitae are so tall that they’re killing the plum tree and causing moss to grow in my yard. Any tips on how I can prune it to allow for more airflow?

One thing I want to be mindful to avoid is pruning the arborvitae in a way that prevents it from growing back and causes bald spots. I’ve learned my lesson the hard way.

Thanks in advance!