25M with Hiatus Hernia

I am young to have HH and have LPR not heartburn or typical acid but 24/7 LPR. I used to have chronic constipation as a child for many years, mostly self inflicted from witholding and megacolon. I am told this is common in autistic children. That dosent affect me anymore and hasn't since I was about 9 I think but I have HH.

I don't know if it was caused by that but online seems it could be. Is there something I can do as PPI's just give me loose stool and even if I try them for a week and go back on them I have a month of loose diorreah. I have just bought gaviacon advance. First time hearing about this liquid as gaviacon double action tried for years and does nothing. Will try 3 times a day for a month.

I am also starting back up iqoro I wish I never stopped. I stopped as I am forgetful then tend to get in bad habits.

Also been fighting for ages to have second endoscopy to go towards surgery. Had one today with GA as an option and had way too much anxiety related to my autism and belong overwhelmed about the sensory part of the needle again as I remember too much from last time. I froze and just didn't show up Awol. Now I have lost my chance without going private. I feel so bad right now but that is how it goes with me. I try so hard to get somewhere but bad anxiety stops me. It depends what my mood is and what I have on at that time and how long notice I have had to prepare.

Does anyone have any advice? Also for such a young age any comments on causes of HH and if I can somehow work to reverse it?