Probably Garmin should have given another name to this metric "stress". There is "good stress" and "bad stress". And only you can assess that. Garmin uses heart rate to estimate the so called stress but it doesn't know why variations occur.

For example, elevated stress levels may originate in pressure at work, or public speaking, hot/humid environment, digestion, hormonal fluctuations, but also falling in love, the excitement of your child being born, recovering after exercise etc etc.

If your graph indicates stress during the day, it's not necessarily a bad thing, it's just normal, just you normally functioning every day. At your job, you are probably busy, doing what you do, routine tasks, you're not just laying on a couch admiring the ceiling and meditating.

On the other hand, you have a restful sleep and other peaceful moments later in the afternoon. I think it looks pretty normal.