Where in the world are you? Location is a lot more useful than zone.

United States, Ohio

There are a lot of small, flowering trees that fairly quickly get to 15 ft. It sounds like you think you need evergreens, but that may not be true. You may not need the privacy during the winter, and deciduous trees can be a decent screen even without leaves.

Where I am, deer browsing is annoying during the summer, but can be horrible in the winter when their normal browse is under snow. So anything deciduous is automatically reasonably deer resistant.

Rutgers deer resistant info https://njaes.rutgers.edu/deer-resistant-plants/