Articulatory phonetics is fundamental knowledge for all speech language pathologists. A small number of second language teachers have this knowledge which allows them to help students position their jaw, tongue and lips correctly for a target sound.
One italki English teacher lists articulatory phonetics in their profile.
Here is a direct link: https://www.italki.com/teacher/5326890
Five italki English teachers list speech therapist in their profile.
One is a certified Speech and Language Pathologist with 14 years experience.
Here is a direct link: https://www.italki.com/teacher/6207172/english
At a less specialized level, phonology is the study of the sound system of a language and is very basic knowledge for English teachers to teach pronunciation effectively.
Twenty-one italki English teachers list phonology in their profiles.
Good luck finding a teacher who meets your needs!