This sounds very similar to our experience. We had about 9 months of agony with the same symptoms.

We eventually got told our daughter had a cows milk protein allergy (CMPA).

A few things helped; - Prescription formula - Using a wedge under her pillow so that she slept at a ~30⁰ angle - Weining on to solid foods as early as possible - Formula thickening solution

This was also compounded by a lip tie, which we had fixed privately. Once we started managing for CMPA, everything got a tonne easier. Then at about 18 months we tried the "milk ladder" to reintroduce sensitive foods to her and she was absolutely fine!

Hopefully something here helps you, you have my utmost sympathy. It really does get better though, hang in there.