I did the afrin test, slept well and woke up without headaches. How to replicate the effects without using afrin?

25M from texas. I was diagnosed with sleep apnea and have been using CPAP for three months. Unfortunately i couldn't see any improvements in fatigue or brain fog.

According to ent/sleep doctor i have nose blockage/ large tonsils and neck fat which was contributing to the obstruction. He told the major factor was due to my neck and asked me to reduce fat. Apparently i have high neck circumference for me height/age. He also ordered allergy testing. I tested badly for dustmites, cockraoch and tree nuts. I have started allergy shots last month. It is a one year treatment and have been using for one year. My doctor also recommended flonase dialy morning and neilmed nasal rinse at night dialy.

Reading about nasal congestions and sleep apnea, i landed in one of the thread where someone in r/uars commented about the uars relief book by a md doctor. He talks about antihistamine helping him alot. And he recommended using afrin just for one night to check whether nasal congestion is the caus.e I did the afrin test and i woke up without headache. It is not day and night difference but i felt calmer and less foggy in my thinking. How can i replicate the same without afrin since we cannot use afrin daily. I tried claritin according to the book but I didn't get same effect. Flonase/neilmed didn't produce the smae effect. I could physically feel my nasal congestion as i lay down even with using Flonase and intake nasal dilator. But with afrin i could feel my left nostril fully free and able to breath clearly. I try to sleep on my side (left). Also the congestion is severe when i lay down compared to standing. Anyone else in same path? any recommendations please?

Also another question about my neck circumference/fat. I felt clamer and also ate within my calorie budget when i slept well. I am unable to lose weight for all these years which has definitely caused some obstruction. But how much of sleep apnea causes overeating? Any tips/advice on how to lose weight while being stressed/unrefreshed due to poor sleep. It seems catch 22 . Thanks a lot. Hoping someone helps me. I have been stuck and struggling for lot of time and finally i have a positive direction.