Trademark for Same Industry but different services

I need to trademark a 4 letter Acroynm for an organization/resource hub im starting. Its targeting a specific segment of the industry I work in, but those 4 letters are already trademark in the same industry as a diploma/degree

Fake example of what I want to trademark:

DIDH: Dietitians in Dental Health
Class 41, a resource hub for education specifically for dietitians in Dentistry

Already trademarked:

DIDH: Degree in International Dental Health
Class 41, education program to obtain a degree