Is there an API or method to retrieve the list of users on site?

Groupware is linking API to check Atlassian usage status.
I need to look up the user list of a specific site, but I can’t find the API.
The Organizational API is not suitable because it gives all users in the organization.
And the Jira API is not suitable because it only provides access to users who use Jira.
What I want is a list of all users on the Site, and it would be perfect if I could additionally filter by product.
Do you have a solution?