Start with an ordinary week
Write down what a normal weekday looks like: when the house is empty, who can take the dog out, and how much time remains for training and coat care. Include the difficult days, not only the weekend you spend outdoors. A realistic plan is more useful than a wish list of personality traits.
Choose the dog as well as the breed
Breed history can help you anticipate interests and care needs, but it cannot describe every individual. Ask a rescue or responsible breeder what they have observed about this dog around visitors, handling, noise and other animals. An adult dog may have a more observable routine than a puppy, although a new home can change behaviour.
Compare the work involved
Compare two or three candidates on the things that will affect your day: exercise, noise, physical strength, grooming and the support they may need when alone. Lower shedding does not mean lower grooming. Small size does not automatically mean low energy. Decide which demands you can meet consistently before considering appearance.
Make a plan for care
Budget for food, equipment, routine veterinary care, insurance or emergency savings, grooming and help when you travel or work. Meet the dog, ask questions and take time to think. If the care plan does not work yet, changing the timing is a useful decision too.
Sources and further reading
Blue Cross: choosing the right dog — https://www.bluecross.org.uk/advice/dog/wellbeing-and-care/choosing-the-right-dog RSPCA: teaching a dog to cope at home alone — https://www.rspca.org.uk/adviceandwelfare/pets/dogs/training/leftalone