My bub doesn't have reflux but did the same thing at 6 months when we first started BLS- try, gag, vomit the milk from feed ages before.

Her gag reflex was just really strong. It wasn't until she was about 8 months that she actually started to swallow food, and she still doesn't eat heaps. I think BLS has been good because it taught her what she can and can't swallow and how to get the food out if it won't go down. At the start, i wasn't thinking that though, it was more like what am i doing, this is crazy stuff.

Babies can survive and thrive just having breastmilk until 12 months or more, so you could just wait another month or two and see how bub goes then with BLS. I didn't completely stop once i had started but (if i was feeling fragile) we might go 3-4 days without offering her food and then try again. Certain foods were more likely to trigger the gag reflex (broccoli) and others she was fine with.

good luck