Q.dwarf evergreens
I’m looking for evergreen trees/bushes that only grow to a height of 4′ to 7′ tall. They need to have branches strong enough to hold up strings of Christmas lights. I live in PA. Zone 7a, I think.

Wow, thanks! Heading right to google images now!

Dwarf Serbian Spruce, Dwarf Blue Rocky Mountain Fir, Tiny Town Dwarf Alberta Spruce, Blue Angel White Pine and Dwarf Japanese Garden Juniper meet your criteria.
Visit your local garden centers and nursery's to see the selections in your region. They may have other choices for you!