Not sure if you've had your procedure yet, when it comes to going under, the biggest contributing factor for issues is if you have sleep apnea.
I had apnea for years (I just had deviated septum surgery last summer, which cleared it up), however, I went under for a Endoscopy/Colonoscopy about 4yrs ago now to determine the same issue sounds like you have (esophageal hernia). During that procedure I stopped breathing, and they had to intubate me.
I had several other surgeries after that (shoulder, knee, deviated septum). I just advised about the sleep apnea and they were prepared.
Note, it has been reported that being on anabolic can cause obstructive sleep apnea, due to the increased weight.
Now, to the Esophageal Hernia, that's a whole different thing. I had mine repaired, as the organ displacement that pushed through the esophageal wall was larger than my heart and pushed against my heart when inflamed.
The healing process for that is slow, and the diet SUCKS! Nothing solid for about 4wks. I prepared for mine having several tubs of protein, fruit and soup (although nothing hot for like 2 wks).
If you have any questions specifically about that surgery and recovery, feel free to reach out.
Cheers and sending luck with healing vibes!!!
PYFT