Constantly sleep deprived, what to do?

I am constantly sleep deprived. I think I get around 6:30-7:30 hours of sleep each night, I wish I could sleep longer but for some reason I can't, however I think my issue is probably with the quality of sleep. These days my muscles always feel used and I have less motivation to exercise because of it. I have had a test for sleep apnea and I do not have it (0.3 events per hour, lowest oxygen saturation was 95%, average of 97%). I have also recorded myself sleeping and I didn't notice anything that seemed alarming. I do leave my mouth open probably a centimeter and a half when I sleep and my sleep quality doesn't really change if I tape my mouth shut.

What should my course of action be to resolve this? I am tired of feeling tired and sore all the time. Getting a full sleep test is pretty expensive I believe so I don't want to do it without doing everything else first. What could my issue be? I have also had full blood works and everything was fine (hormones, antibodies, vitamins, etc), so I think my issue is definitely a sleep issue, if not a breathing issue.

If it is relevant I also have bruxism (got a splint when I was 15ish, not stress related), Seborrheic dermatitis and somewhat frequent nosebleeds (I infrequently wake up with blood in my nose).

Thanks for any help.