After a fundoplication, individuakls are unable to belch. Accu,ulation on gas
in th estomach or small intestine can cause the gas
bloat syndrome that you describe. The offending gas may come from digested food although usually it is the result of swallowed air. the air can come from outh breathing or talking when eating.
The take down of the fundoplication should have relieved your symptoms. The propulsid should also be helpful.