Snoring With Mouth Closed

Hey... I didn't realize I snored this much until my girlfriend told me. I did a lot of research into snoring and here are some facts about myself:

• 5' 8". 140 pounds.
• I snore with my mouth closed.
• I'm a side sleeper.
• I can re-create my snoring even while awake. The snoring seems to come at the back of my throat instead of my nose area.
• When I sleep on one side, my nose congests/closes pretty badly and I can't breathe out of that nostril very well. If I swap sides, that nasal congestion moves to the other nostril.
• I don't drink much alcohol. Very recreational.

I'm so lost. I ordered a product that will prevent my jaw from sliding back. But I'm able to snore even if I purposely jut my lower jaw forward and tongue forward to prevent them from blocking my airway.