Server-side synchronization now allows tracking of emails, appointments, and tasks in Outlook and adds a new Category Tracked to Dynamics 365
For version 9.1.0.4039 or higher, category Tracked to Dynamics 365 is by default on, We can disable this for an organization using Admin settings

Disable or Remove Category Tracked to Dynamics 365 on all Exchange mailboxes of the Dynamics 365
There are 2 Option
- Remove Category Tracked to Dynamics 365 using setting from OrgDBOrgSetting/Releases and same can be used to Enable setting
https://github.com/seanmcne/OrgDbOrgSettings/releases/ - From admin.powerplateform.microsoft.com disable setting-> Access https://admin.powerplatform.microsoft.com as an administrator
-> On the Environments tab, click … next to the name of the environment and then click Settings.
-> Click Email Tracking.
-> Locate the option People can use categories to track emails and appointments and switch the option to Off.
->Disabling this setting will remove the category Tracked to Dynamics 365Â on all Exchange mailboxes of the Dynamics 365 for Customer Engagement organization which have server-side synchronization enabled in about 15 minutes.