How to identify each unique user through Connect App

Hi all,

Since Atlassian decision seems to end support for 3LO apps, we are looking to Connect App to give the possibility to integrate Jira on our platform. However, after reading through your documentation, some questions still persist surrounding user authentication and identification.
Our business logic requires us to be able to link various Jira actions’ (example: user created a new issue) to requests generated by users on our platform.
Previously this was achieved by linking an access token to one of our user accounts, and requesting authenticated information on the fly through the Jira API (example: /myself or currentUser() function in JQL).
We have noticed that there is authentication information passed through the Connect App, but this appears to be the user information of the admin that installed the Connect App on the host (although we could be mistaken about this one).
Could you either give us a brief explanation or point us to some documentation that shows that it is possible to identify each unique user (with an access token for example) through our Connect App, and how an end-user would be able to ‘link’ his Jira account to our own user account.

Thank you very much for your help