You can buy the Stryd + Membership bundle even if you already have the Stryd Membership. Doing this may pause your current Stryd training plan. Pausing an existing training plan will hide all workouts in the plan from your calendar view until you resume the plan.
To resume a training plan:
On your mobile device, go to Stryd -> "Settings" -> "Training Plans"
Open the menu option either by selecting the plan (iOS) or holding a long press (Android) on the training plan you want to pause. Select "Resume".