Given your age and accommodations, I would encourage you to look at larger breeds that require less “maintenance.” Good examples include St. Bernards, Malamutes, Mastiffs, and Great Danes. They’re giant animals with a lot of power if you’re worried about protection, but they’re generally sedentary and require little exercise.
Small dogs are great, sure, but unless you’re going to adopt older shelter dogs, dealing with small dogs when they’re puppies can be a hassle, and they require a lot of exercise to keep them from bouncing off the walls.
I’m half your age and have a border collie and an elderly dachshund, and together they’re an absolute handful. I can’t imagine trying to keep them corralled.
Also, have you considered cats?
I imeediately thought "Great Pyrenees". However they can be huge. There is a solution, though: A Pyrenees/lab mix. They are called Pyradors. Pyrenees are the most mellow big dog I know. My child accidentally steps on his feet and tail of our Pyr mix, and the dog is simply glad for the human interaction.
Plus, the dog lays around all day and has low caloric requirements. He weighs 85 lbs but eats the same amount as his 45 lb sister!
Malamutes dig, chew, and need to be brushed daily once they start blowing their voluminous coats.