Atera has already onboarded the custom fields option, and they were populated for each customer's and their agents, and it can be improved with the following idea:

Since the custom fields data have to keep changes and updates on a regular basis and the same data has to be maintained on a real-time basis, importing bulk data into custom fields using templates can be helpful to technicians for filling data faster into custom fields and avoiding manual work to fill those fields.
As you are aware, custom fields are those fields that are unique and different from the requirements of every account and their technicians.

Suggestions: The feature of bulk importing data into custom fields can be added to Import Data from the admin panel.

https://app.atera.com/new/admin/import

Step 1: Select the data you wish to import (custom fields).
Step 2: Prepare the import file (CSV import template for custom fields).
Step 3: Import the file.