I have often been asked "How do I know if this therapist will be right for me?" The Guardian article mentions the parallel of 'dating'. You don't necessarily date the first person you meet or read about, do you? There are some obvious criteria you might be looking for such as the therapist's location, how much they charge, their flexibility of work hours which would fit around you, their approach, their experience etc. Then its about your relational chemistry and general fit. That is much harder to predict or control.
One example of trying to get the right 'fit' is when a person who is 'neuro spicey' (i.e., neurodiverse). I've been asked for example, if a person who is on the autistic spectrum should actively seek a therapist who is similarly on the spectrum? That is an interesting question and it has a complicated answer:
1) It may be helpful to have someone who understands first hand what you might be going through, i.e., has some expertise in this area. However, this only becomes relevant if the issues you are wanting to explore in therapy are related to neurodiversity. It may be that you are wanting help to understand your partner who is 'neurotypical'. In this case, maybe a neurotypical therapist would be more suitable.
2) I'd also say that the therapist's identity of being on the spectrum (or whatever) is just one factor to consider. You could have 10 therapists who say they are on the spectrum and they are all going to be different in their relational style and therapeutic approach.
3) Perhaps what is more important is to have a therapist who is knowledgeable about neurodiversity and appreciates what it means to be neurodiverse (e.g., perhaps they have a child who is on the spectrum). If the therapist doesn't have some awareness of the issues, or they dismiss or diminish your concerns re: neurodiversity, then they are probably not the right therapist for you.