I don't have a lisenced emotional support animal. My dogs are a huge part of my life though and I'm as much of an emotional support human to my current dog than he is an emotional support animal to me.
Just a thought on dogs in general...
The breed doesn't matter that much. Dogs are in general affectionate and can be trained easily with positive reinforcement. Look for Zak George on Youtube if you're interested in positive training methods.
Chosing the dog with the right temperament that meets your needs and your lifestyle is way more important than the breed. Take some time, sit down take pen and paper and write down what you actually need and want in a dog. Not what breed, what he or she should look like but actually what you imagine your life with a dog. Do you want a companion who is active and is always up for another run after you just arrived home from the dog park, the next adventure, the next squirrel to chase... Or are you looking for a dog, who's rather calm and resilient to stress.
A lot of people who never had a dog before (and also those who did) chose the dog that is the most affectionate. Which means the most enthusiastic and active, the little go-getter who climbs your lap 10 seconds in. Those are often the active ones, those who can't wait for the next adventure and sometimes those who have higher stress levels themselves. I had one of those. I loved her to bits but her level of activity and need for a 'job' was not the last reason why we ended up training for search and rescue.
I've rarely heard anyone say I don't want an active dog. The problem with it is often that people underestimate 'active dog' and overestimate their own level of activity. I chose my current dog carefully. He's on the lower middle end of active. He's always happy to come for a walk but he's also ok with only short walks on rainy days without getting stressed out. He's also much easier to train because of this. He's able to pay attention, to wait, to process what is happening, to listen and he isn't as easily frustrated when I'm making mistakes or fail to communicate what I want from him and he can be motivated to do all sort of things very easily.
Most dogs were bred to do certain jobs. Hunting, protecting, herding... German Shepherds are known to be on the more neurotic side, most hunting dogs are more on the hyperactive, herding dogs as in Border Collie, well... let's not talk about them if you're not planning on getting sheep as well. There are crazy Labradors who are completely out of control because they are so f*cking happy all the time and Poodles were initially bred for hunging.
All dogs can be easily trained with the right method under the right circumstances. There will be cool German Shepherds, a couple of calmer Border Collies, very very few hunting breeds who aren't interested in chasing... The real question is, does the specific dog fit to what you want him or her to do and be and what will your life look like for the next 15 years.
For an emotional support dog, consider chosing the calm and stoic one, who's sometimes perceived as "slow" or "a little dumb" ;) Don't go for the active one if you're not 100% sure, you're on the high end of active yourself. Even consider getting a rescue dog who's already a year or older. You will know what you get when it comes to temperament and there are very good dogs who would probably be a good fit. The dog I trained for search and rescue was almost 3 when she moved in with us. It's absolutely not true, that they can't learn all the things you need them to know when they are not a puppy anymore. As long as they had good enough socialization, they'll be fine and it's often even easier to train them when they are over those cute but also difficult phases of puberty and chewing everything they can get their little teeth on.