Gas, bloating/discomfort, flatullence (sometimes nausea, rarely) after eating, but good appetite, no blood, no pain. What could it be?

Poor digestion . The process starts with your mouth. Saliva, chewing well, sips of water with each couple of bites, eating slower and talking less while at it helps. Smaller meals. Your symptoms seem to be triggered by poor digestion. Something is off. Irritable bowel syndrome can cause similar symptoms. Meal hygiene is very important.