Can I delete a team member and not lose the time tracked on projects?

No, you cannot completely delete a team member without losing the tracked time on projects, as it will also be deleted. Though, you can lock a member, so he/she won't have access to your projects. For this, perform the steps below:

1. Go to the Members page.
2. Locate the member you wish to lock in the list.
3. Click the ellipsis menu next to his/her name and select Lock Member.
4. The member's status is changed to Locked.

Note: When a member is locked, all data related to them will be preserved, but access to the workspace will be restricted. Their data can still be used for historical purposes. If needed, the member can be unlocked later by selecting the appropriate option from the ellipsis menu.

If you are absolutely sure that you want to completely delete a member along with all his/her data, select Delete Member from the ellipsis menu. 

You will see the dialog box where you can either confirm the deletion or choose to lock the member instead. So, choose the option you need and confirm your choice.

Note: Remember that deleting a member will result in the deletion of all their data from the workspace, including tracked time, created timesheets, time off requests, and all mentions of the member in projects and tasks.