Users in a Teams Workspace will have access to both their Individual and Teams Workspaces.
If you join a Team where you are not the Admin/account owner, your Individual subscription will remain the same. For example, if you are currently on the Basic plan,your Individual Workspace will have the same Basic plan features that it had before. Projects that you create on the Teams Workspace will have access to the upgraded features of the Teams plan.
If you join a Team as the Admin/account owner, you will have access to the upgraded Teams features in both your Individual Workspace and the shared Teams Workspace.