Not enough deep sleep, what to do?

Since I'm always pretty tired in the morning, I tracked my sleep with a good smartwatch (I know you shouldn't rely on it). It turned out that I get a lot of light sleep and very little deep sleep. My REM sleep phase seems to be fine. I should mention that I don't consume caffeine in the evening, and my room is well-lit and well-ventilated, so I wanted to ask if anyone knows how I can get my problem under control.