We have a roper frig that we use for vaccine storage, the freezer does not stay cold enought for their storage; if we adjust to freezer temp for vaccines then refrigerator is too cold for storage

Good day,
Usually caused by the machine in a cool area or room, along with the machine not getting enough door action, both freezer and fresh food.

Domestic refrigerators are designed to be used as just that. Domestic refrigerators.
Normal kitchen temperatures, followed by minimum of 7 freezer door openings per day spread over 14 hours as well as 22 to 26 fresh food door openings over the same period of time.

In other words, it's not getting enough activity daily. Common problem in doctor offices.

The best model for that type of application in the past was the Amana bottom freezer model. where the primary control was located in the freezer, nailing the freezer temp, and the top controlled by a pneumatic damper controlling the fresh food section, but I do not know if their current model still uses that system.

One option,space permitting is a small chest type freezer added to what you have.