There are XF MarketPlace solutions you may leverage for this. Developed by OneStream with no additional cost.
Security Audit Reports
Set the Start Date and End Date at the top of the dashboard then Refresh. To derive active user count, take the difference between Total Users and Inactive Users from the table at the top left of the dashboard. Active Users would include any user who has logged on at least once during the set date range.
Standard Application Reports
Includes User Log Activity reports. Could use this to get logon count by user.