If you manage to disable the suggested workouts feature on your Garmin Watch, then there is a quick way to re-enable it.
Go to your "Race calendar" > Select your event > Click start/stop button and an option for "Daily suggestions" will appear. You can configure it from here.
This differs from Garmin's own suggestions, which states that the "Daily workout" option will appear under "Run/Bike" > settings > training. It doesn't appear on mine and every time I end up having to figure it out again... So here we are.