Best suggestion is get a sleep study done by consulting a pulmonologist or ENT specialist. According to the sleep report best possible advice cn be given. This will help you a lot in longterm by preventing stroke, Ventilator support, cardiac arrest and many more. Diet and active lifestyle is the most important that help reduce weight

get yourself evaluated for osa

Take a lukewarm water before sleeping and change the position

Try to sleep in either in right or left lateral position than lying on stomach. If you have symptoms of nose block and allergic rhinitis, u can try steam inhalation before going to sleep. Avoid taking sedatives for sleep.