I had a weak swallow from polio, also an LES, which allowed reflux, but PPIs kept pH high enough to not cause much damage.
I had reflux mainly when I ate a trigger food - ingredients I do not tolerate. I learned to control most of the reflux by avoiding my triggers.
Then an accident pushed my stomach partway into my chest and my LES was left wide
open. Without PPIs (off 10 days for BRAVO test) my pH was 1 all the time.