For just logins, there are three methods. You can view/export the usage logs for Analytics, use the UM API which includes login dates for the Experience Cloud, there is also a UI tool that is being prepared for admins that will aggregate the data from the UM API, such as last login date.
However, by using UM API, you are looking at logins for any Experience Cloud product and it doesn't demonstrate any additional activity within Analytics. If you want more information on just Analytics, you will need to restrict your view to the usage logs available through Analytics. So it would be a manual export to PDF. If you wanted to automate the collection, you would need API capabilities.
There is a method, but I believe it is a v1.3 API which is unsupported, as mentioned in the link shared by @Gigazelle .
Also, the UM API will not give you actual usage metrics.
There is no longer convenient documentation for the API, but it may still work if you can find out how to form the request and as long as the account using it has the "Logs Access" and "Web Service Access" permissions within the Admin Console. However, all v1.3 and v1.4 API are meant to be deprecated this year, and it wouldn't necessarily be worth your time trying to use the existing method for exporting the logs. However, there are several other threads that mention adding this or related features. For example: