I had two beagles rescued from an animal testing laboratory, and neither ever showed any interest in the human bed. I think since they were already adults when they were freed, it didn't occur to them to try. They had their own beds at the foot of ours. Every night, my husband and I would get on the floor and cuddle with them in their beds. Once we took them to a dog-friendly hotel for a weekend and they did hang out in bed with us a little.
One of those boys died almost two years ago, the other is still with us. We fostered several other dogs until we foster-failed with a girl beagle, also from a laboratory but much younger. She sleeps in the human bed about half the time.