Very unlikely. Even large corporate employers don't give time off for most federal holidays. I have a cushy tech job and still have to work on MLK day, President's Day, Veteran's Day, Columbus Day.
The only exception to this would be companies (and schools) that will use Juneteenth as an education day instead of giving the day off. (I hope companies don't do that. If I want to get educated I have books and the Internet)