How to track fragmented sleep?

Hi all! I used bearable for 2 weeks and it's been insightful so far.

I'm still trying to understand how to track fragmented sleep the best. I usually wake up several times per night, sometimes for hours, and I'd like to be able to track it.

Do I add a custom symptom? Or do I extract the time I didn't sleep from the overall time?

Does connecting a sleep tracker work? (I don't like using mainstream trackers for, well, trackers, but willing to try).

Improving sleep is one of the reasons I started using bearable, and I really want to make it work.