I haven't read the full thread but my experience of PPIs were I went to the Dr with a tickly throat and ended up on omeprazole for 8 years. Dr never did any further investigations or gave any warnings about long term use, just said keep using them if needed.
Any time I tried to stop the horrible burning and pain between my shoulder blades would start within 12-24 hours.
I stopped them over a year ago - what allowed me to stop them was significant weight loss and change of diet (supported by weight loss injections).
This then made it easier to spot the triggers - anything tomato based, chocolate, greek yoghurt and some other yoghurts, rhubarb (miss that one!), fizzy drinks, citrus, excessive sugar. Another one is leaving too long between meals. If I keep away from my known triggers I am usually ok, if I eat one I can mostly manage with rennies or if bad gavison advance. Sleeping on left side really does make a difference. I do still sometimes get bad attacks - some cheesy baked beans on toast were a nightmare last week and nothing was helping!
The diet changes are restrictive, but I was experiencing unpleasant B12 and magnesium deficiency symptoms from being on PPIs for so long I had to do something.
Good luck with your gastro appointment, hope they are able to do something to bring some relief.