A reputable psychologist or therapist will be DELIGHTED to talk about where they graduated from and what they specialized in, and you can check. (They’ll also have a provider number, which the non-quals will not have.)
The big reason to avoid the uncredentialed ones? Especially any that claim to do marriage & family work? STRONG associations with the Adoption as Missionary Field set, the conversion therapy set, and forcible compliance for children. It’s not 100%, but reputable psych doesn’t do that shit.