Here’s my two cents for what it’s worth:
1. There is no scientific evidence to support the concept of a hypoallergenic dog. Ask your allergist.
2. Small dogs being smaller produce less dander.
3. Some dogs are less allergenic to some people than others. This depends on the two individuals (dog and human) involved
4. Don’t let people tell you the only “responsible” or “ethical” way to obtain a dog is to adopt one. There are pros and cons to adoption vs purchasing a dog. Adoption does a solid for a dog with no home, maybe saves a life but can be a bit of a crapshoot at times. Buying a dog means you can get a dog who is often true to type, which means a lot if you value performance in a dog- hunting, agility, obedience, scent work, herding, or the recreational “dogsport” versions of things dogs were bred to do.
I personally love dachshunds but for a small dog recommendation for your typical pet owner, I am a fan of the papillon. They are smart, lively but being small don’t need hours of exercise, and they are typically cheerful and good natured.