New to you post. I know that my mothers doctor told her to raise the head side of the bed. My Dad cut 2 4x4’s placing one each under each bed foot. It helped and it was not noticeable to Dad. I slept at a friends house while visiting from out of town and she had a bed which had a hospital like bed remote that customized the sleeping positions one each side. It was a feature that I fell in love with. In your case you could raise the head and chest to a position that is comfortable even if for reasons that have nothing to do with hiatal hernia; meaning: if you can afford it you may like it non~the ~less.
I’ve been seeing commercials on tv a lot lately for a brand called “ Craftmatic “ and 2 selling points besides the obvious is that it costs less than years ago when people first purchased them and now the sleeping surface has many options including “ memory foam “ I’m not sure if sleeping on memory foam is a plus or minus for you. I don’t care for my rather expensive memory foam pillow that I got sold on. It is best used on my bed when watching TV